How can my boyfriend divorce his wife ASAP?

Okay so for context, my boyfriend and I have been in a relationship for more than a year now. Everything is going fine but the thing is that he has a WIFE (technically). They got married around three years ago, it was an arranged marriage as he and I are from different castes. We are from a third world country so caste does really matter here but we dgaf at all. They have been separated for two years now and don't live together though she used to come back once in a while and act like she has changed now and then go back to her normal evil self but that was before my bf and I got together. They're separated because after the arranged marriage, she humiliated and verbally abused my boyfriend and his mother. She used to torture them both verbally and financially claiming that he didn't do anything for her at all.

The thing is, my boyfriend's family isn't very strict (inside their own family). They have maids to do literally everything, they would agree to everything she said, call in a massage therapist for her twice a week. Let her go on trips and all and paid for literally everything. They were the ones who paid around 100k in USD currency (which is enough to buy a house in my country) for the wedding. She used to work when she wasn't married but then stopped working after marriage. They don't have kids as my bf stopped being attracted to her(in all aspects) after their first year. She would publicly abuse him and make him feel small and her family would support her.

I also didn't believe my bf when he told me all this but then he showed me a secret recording of his family talking about all this, visibility traumatized and he showed me some proof as well. From the recording, I also heard that when my bfs dad was going through an emergency operation, his family asked her to come visit him once as if the operation went south, they may never see him again. She straight out refused and talked like she wanted him to die (may that never happen). The main reason why they haven't gotten divorced yet is because my boyfriend's family is really controversial on all that. To them, society and what it says really matters so even though they're not happy with her and don't want her around, they are confused on what to do and how to do it. They have talked about divorce but everything isn't really finalized yet. She is currently living with her own parents and she used to go to her own house (which is like really far from my bfs house in literally another province) even after she got married and stay here for months and not pick up calls from my bfs parents or anyone at all. Then she would as her dad or brothers to talk to my bfs parents and they would kind of be really rude too.

I cannot tell everything here but I have seen enough proof that I know all of this is true. He has told me that after around 3 month, they're going to have a family meeting (his and her families) and things should be okay after that but I'm just too scared. I don't know what to do.

And the thing is that he has been planning to propose for over three months now. I'm the one who has put it on hold until everything is finalized. Am I being unreasonable for that? He doesn't think so but I do. I feel really bad whenever I see him cry because of the things she would make him go through (again I cannot say it on here). But I just, I don't know. Should I say yes to him now and then wait until everything finalizes to make future plans? We also planned on leaving the country together after my finals. What should I do!! I need advice on so many things..