First off, I'd just say either talk to your dad or some other respectable Christian figure (I would generally consider that to be a youth leader in my church) that has gone through extensive studies about your beliefs. I know you've probably been reading "anti"-Christian-belief articles/information, but you'll find that there is a lot of support for what the Bible says outside of the Bible or religious thoughts (meaning somewhat scientific to all scientific/archeology). Some of the best ways to get real, logical answers (religious or not) is to ask the experts and avoid the internet. Books are one good source for that (PM me and I could recommend you a couple that you may or may not have read, but they're very good). That could at least lean you more towards believing in God...there's no hard proof, but there is evidence (outside of, "I see the sun, hooray!"). I think with many many GOOD answers from "Christianity experts" to the questions that have lead you from Christianity, you will have an easier time talking to your dad about it.
If you're completely uninteresting in perhaps going back to Christianity (not my personal recommendation...I don't buy into the attacks on Christianity/religions for not being logical), then don't get pro-Christianity answers. Skip that step, but go back and talk to your dad. You should talk about everything that you possibly can (which will involve religion) in hopes to mend your relationship. As a Christian, he should be "upset", but not mad. He should try to "bring you back", but never force you. He's handling it the wrong way.
Either way, if you have any hopes of fixing your relationship, you'll be hearing some pro-Christianity talk...you could get all of the info "under your belt" by getting certain, good pro-Christianity answers and have an easier time talking to your dad, or you can go straight to him...but I know he'll try to bring you back, and he will likely do a much worse job at that then an "expert" (whether you personally talk to them or not) would do. I don't know if that would result in the best sort of talk for you guys to try and mend your relationship on.
I may sound confusing...yeah, probably. Just know that it's never wrong to question your faith. Doubting? Yeah, but questioning should prompt us to seek answers...which can change our views either way depending on the view of the source we get the answers from (even some pro-Christian sources are so poor that they make Christianity sound stupid).
Christianity is basically all faith, but it's logical faith. There is plenty of knowledge out there to back Christianity...it's not completely blind faith. That's a mistake some people make about it. (Not necessarily a direct reply to the OP, but just in general)
In short, as a Christian, I know why your dad feels this way, but he's handling it the wrong way. I don't think he should just accept you, but he should try to bring you back through logical reasoning/arguments (by arguments I mean non-aggressive). I would personally try to persuade you back to Christianity, but I'm not an expert...I myself still have questions and try to find answers (So I bring up the ask an expert with pro-Christianity)...so you're dad will do the same, probably even more so because you are his son. He shouldn't do it through anger, though...that's wrong. So I think it's up to you to mend your relationship, talk to him about religious thoughts, etc. Hopefully that all goes well, but I know what you're in for.
Kinda off topic, but this is actually something I thought on my own in 5th grade (I know I wasn't the first, but I've seen it used afterwards): What do you have to lose in being Christian? If it's all a lie, big deal. At least you can say you tried to live a good life. If it is truth...well, yeah, you know the rest. It's a win-win situation (unless some other religion is true, which is not good...better than believing nothing though, I think).
I'm sorry for going on and on...I enjoy discussing this with some people or trying to help them in some way (so you could PM me if needed)...and I also am waiting around for my friends to finish up something for our school work.