Ayatullah Muslim Dawari, a very close student of Ayatullah Khui, in his rijaal book, fixes the sanad of Kitab Sulaym in a very interesting way...

"Usool Ilm Al-Rijaal" of Ayatullah Muslim Dawari, v 1, pgs 278-280, he writes:

'And the author Sulaym bin Qays al Hilaali is EMINENT and TRUSTWORTHY'

Refer : Rijaal Kashi, v 1, pg 321 (Aal-al-Bayt institution)

Mo'jam Rijaal Hadith, v 9, pg 230, fifth edition

Further continued :

'And he mentioned in his translation that he fled from Al-Hajjaj and sought refuge with Aban bin Abi Ayyash, and stayed with him until the end of his life. And he summoned Aban in his last days, and said to him: O Aban, I have been close to you, and I have not seen anything from you except what I like. And I have books that I have heard it from trustworthy people, and I wrote them with my own hands, in which there are hadiths which I do not like to explicit to the people, because people deny it and glorify it, and it is a right, which I took from the people of truth, jurisprudence, truthfulness, and righteousness. on the authority of Ali bin Abi Talib, peace be upon him, Salman Al-Farsi, and Abu Dhar Al-Ghaffari, Al-Miqdad bin Al-Aswad, and there is no hadith from one of them that I hear from one of them except that I asked about the other until they all agreed on it'

Refer : Bihar al-Anwaar, v 1, pg 78

Further continued :

'As for the book, there was a dispute about it. Some of them argued that the book is one of the GREATEST PRINCIPLES (Usool), and it was reported on the authority of Al-Nomani - one of the scholars of the fourth century - 'that the book of Sulaym is one of the largest books of Usool that the Shiites referred to and relied upon'

Refer: al-Ghayba of Nomani, First edition, pg 101

Continued:

'And Ibn-al-Ghadairi went upto saying 'that the book is fabricated and there is no doubt in that and he mentioned proofs of his claim.

First: The narrator of the book is different, it was said: He is Aban bin Abi Ayyash, and it was said: He is Ibrahim bin Omar Al-Yamani, on the authority of Omar bin Uthaina, so the path to it is different.

Second: The book includes matters that cannot be believed, such as: Muhammad Ibn Abi Bakr admonished his father upon his death, and the case is that the age of Muhammad Ibn Abi Bakr upon the death of his father was three years, another example is of the thirteen Imams'

Refer: Tanqih al Maqaal, v 2, old edition, pg 52

Continued:

'Sheikh Al-Mufid went to a middle opinion between the two sayings, as he mentioned while responding to a narration that Sheikh Al-Saduq adhered to, based on the book of Sulaym. The narration is CORRECT in meaning, except that the book is unreliable because it contains a mixture of the AUTHENTIC and other (narrations), as if it had been showered in the book, and the narrations were mixed in it. It must be distinguished in order to know the CORRECT one from the other' 

Refer: Tashih-al-I'tiqaad, first edition, pg 149

Continued:

'From all of this it is known that the versions of the book are different, and because of their differences they (ie. scholars) differed in it. (Means due to the different versions received by the different scholars, it's AUTHENTICITY is also differed depending upon the scholars). Some say that it is fabricated like Ibn-al-Ghadha'iri, and some say that it is one of the GREATEST Usool, such as Al-Nu’mani. It bears witness to the latter that Shaykh Najashi when mentioned the book did not argue that it was fabricated, and this is a proof that it is SAFE from the fabrication'

Refer: Rijaal Najashi, v 1, first edition, pg 68

Also al-Fihrist, second edition, (Al-Najaf Al-Ashraf), pg 107

Continued:

'And as for the way to the book, Al-Aqiqi mentioned that the only narrator of the book is Aban bin Abi Ayyash, but the understanding from the words of Sheikh Najashi that the book has MULTIPLE PATHS, they mentioned that Othman bin Isa, Hammad bin Isa, and Hammad bin Othman narrated the book. On the authority of Ibrahim bin Omar al-Yamani, on the authority of Aban once, and on the authority of Ibrahim, on the authority of Sulaym another time'

Rijal-Al-Alamah - Second Edition, (Al-Najaf Al-Ashraf), pg 83

Rijaal Najashi, v 1, first edition, pg 69, and in, second edition, pg 107

Continued:

'It has occurred in the narrations of the book on what was mentioned in the insights and the specialization, with their chain of transmission on the authority of Ali bin Jafar al-Hadrami, on the authority of Sulaym, and in some copies of the book on the authority of Muammar bin Rashid, on the authority of Aban, on the authority of Sulaym, and in some of them Aban bin Taghlib. If it is not an attribution to Aban bin Abi Ayyash, and the result is that the path is not confined to Aban bin Abi Ayyash, then the words of Al-Aqiqi are misplaced, and if the path was limited to Aban, then it is weak, and if it is multiple then it is CORRECT. The book is considered VALID because one of the paths ends with Ibrahim bin Omar Al-Yamani, who is TRUSTWORTHY, except in the path of Shaykh Najashi. So the book (through the path of) Shaykh Najashi is weak. We cannot rely on this book (through this path), and rely on it with regard to rulings, even if the author considered it as one of the RELIABLE books. But we found another path other than what the owner of Al-Wasa’il mentioned in his permit to Al-Fadil Al-Mashhadi, and it is the path of the owner of Al-Wasa’il himself to Al-Kulayni'

Refer: Bihaar al Anwaar, v 110, pg 120

Continued:

'And this path, even if it ends in Aban, it is not documented. Shaykh Najashi had TWO PATHS and one of them was RELIABLE and did not mention the difference in transcription, so it is possible to construct the chain of transmission and the book is CORRECT, and the CORRECTION of the path is based on the narration of Hammad bin Issa, on the authority of Ibrahim bin Omar, on the authority of Sulaym, and this is a VALID path. It was mentioned by Shaykh Najashi that the path of Al-Kulayni which ends with Hammad is AUTHENTIC and after him it ends with Aban, which is weak. So we take what is before Hammad from the sanad of al-Kulayni, and what is after Hammad from the sanad of al-Najashi, so the sanad is VALID. On this basis the book of Sulaym is AUTHENTIC. On this basis the book of Sulaym is above the doubts. It can be TRUSTED upon, and this is the claim of the author of Al-Wasail'

Fadlullah in his book Ta’ammulat fi Afaq al-Imam al-Kazim ع , pg 40, states:

'The events from which Sayyidah Zahra (sa) suffered are not confined to the Book of Sulaym, nor do they end there either. This book and its sources, are narrated by Sunnis and Shi’as. What is quoted from Sulaym’s book are only a few traditions. The differences among the narratives within the same report and among the sources on which they rely is a true witness testifying to the transmission being from more than one book. The AUTHENTICITY of Kitab Sulaym ibn Qays and the ACCEPTANCE of its narratives do not hinge on the venue leading to him, openly and directly. Suffices to accept its narratives the fact that numerous scholars have already ACCEPTED them and are PLEASED with them. They quote them and clearly rely on them, paying no heed to what is said about the men leading to his venue. This is a strong testimony to the fact that this book is above being criticized. It is firmly and strongly established so long as the proofs for its AUTHENTICITY are to the extent that no noteworthy doubt can ever scratch its ACCURACY. The outcome is this: I have stated that Sulaym’s book has been received by the nation with ACCEPTANCE and APPRECIATION just as it received other reliable Imamite books even when some scholars have discussed some of its narratives. Such is meant by Grand Ayatollah Sayyid [Abul-Qasim] al-Khoei, may Allah have mercy on his soul, when he DEFENDED the contents of the book. What he stated came out to accept the evidence of the report of AUTHENTICITY rather than the authenticated one. By my life, one who decides that it is alright to accept Sunni narratives without any reservation or minute investigation of their references, once he trusts the accuracy of their contents and finds no reason for any lies therein, has no right to discuss Sulaym’s book which is one of the MOST IMPORTANT books that uphold the right sect without straying from its path'

(The chain apart from Aban bin Abi Ayyash as mentioned by Shaikh Najashi in his Rijaal)