the answers seem to support what I was thinking, that if the application process just takes long enough, the applicant will receive the 10 year green card without an ROC being necessary.
It’s not directly about sending him back as someone here suggested, which to my understanding is not even an option at this point.
It is mostly about shedding some light into what was going on in those years in that marriage and potential fraud, as my SIL didn’t recall signing any ROC documents, which now makes sense.
I do not have a full understanding of everything, but from what I understand so far, there was a lot of abuse going on, mental and financial abuse 100% for sure, and it potentially even physical, at least that’s what my gut tells me, I could be wrong but a few things that were mentioned indicate that.
Hence my interest in shedding a bit of light into some aspects of that marriage.
Thank you everyone for the helpful answers.