I had a very bumpy relationship with my mother. I once cut off all communication with her for 8 years. I didn't want to be hating her when she passed on, so I made up with her and had, what was normal for us a relationship. I did not ignore what she had done to hurt me, but I didn't bring it up either. I chose to not let it eat me up and make me regret having hard feelings when she passed. She died 2 years ago and I am glad I got back together with her before she did.

IMO you should try to contact your dad. I'd call once and/or email once. That way you did your part and should have no regrets when the time comes. But don't beat yourself up if you don't want to contact him. Make the decision that is best for your peace of mind.