I know I am really, really late in responding to this, but if somebody isn't living their life for the Lord and not even trying, you aren't bound to them in any way. Christ said that he that forsaketh not his father or his mother, or sister, cannot be his disciple. What that means is if you put anything before God (in importance) you can't be his disciple. His word also says not to have fellowship with unbelievers. If your dad got saved and asked you for forgiveness, then you should forgive him, because we all need forgiveness. There are people who have done me big-time wrong, and while I am not bitter and I don't hold a grudge against them, I don't want anything to do with them. Before God, there is nothing wrong with that. All of the questions you have are answered in the Word of God.