Sounds like you know what you want, you know your values, and you know what you will and won’t put up with.

It also sounds like he needs to be further away from his family, not closer to them. But he may see things differently.

The downside of putting down an ultimatum is that if you don’t get what you demand, you’ll have to follow through. But I can see how being on your own may be preferable. If his relationship to his unreasonable, rude and abusive father is more important than his relationship to you, why be with him?