You have no obligation to him, it doesn't matter if he's your father. You do not need to contact him, for any reason. Only contact him when/if you want to. I know what its like to have an abusive parent and not want to have anything to do with them, but keep crawling back to them, whether its hoping they'll change or out of pity. Sometimes for me it's even out of necessity financially, which is the worst. So if you don't absolutely need to, then don't. It's hard but it gets easier. For example, if you go no-contact the first year, but feel super guilty, then send a card or a quick phone call but leave it at that and move on with your day. Don't get sucked into any emotional blackmail or manipulative games. Be aware of that but you can still put on a nice face and a short conversation and be done with it. That's what I do these days. I get pissed at myself for being nice - but if it means keeping the peace, then so be it.