I think it’s best to straght ghost them, but I haven’t personal had to do that to family-- only family friends. They won’t change their views for you, it’s really just for your own mental health and a clean cut is so much more satisfying.

It’s always probably they’ll change on their own eventually and want to reconcile and if that happens, there’s always a way to find someone if one tries hard enough. And if he doesn’t change? People like that deserve to die alone.