I am about to see my father he is 76 yrs, after 38 years of rejection, any tips?

I was 15 had some kind of stupid fight. I didn't want to tell my grandmother (now dead) were I was going. My mother and grandmother force me to talk on the phone, because he wouldn't pay child support if I didn't talk to him. He heard me say no I don't want to talk to him. He was nasty on the phone. I said I didn't want to talk to you, but they force me and hang up, that was 38 yrs ago.I tried 3 times in my life time, 18, 20, 30 yrs old. I invited him to my graduation 18, but didn't want to come, I invited him to the wedding at 20 yrs old. He said why should I do you the favor. I called at 30 yrs old. He said He had to make an appointment. I got mad and said I'll call you, I'll call you (You think I should of gotten mad?) I thought why would I have to make an appointment or why did he say that. He should of kept quite an said o.k. He has not once tried to connect me, not once. Why? He is 76 yrs old. I want to connect with him before he dies. I want to give him one last chance or I will regret it, but I am afraid of rejection. I know where he lives, today I am going over there, without him knowing it, it's kind of far, his phone number is unlisted. I don't know how to go about it, what do I do, my friend is coming too, He has no relative. I think they are all dead. What should I say, what if he reject me again. I am so afraid to see him. He was so abusive mentally and physically, but he is 76 yrs old. He does not have much time to live. Help me find the word to talk to him. P.S I know the child support shouldn't has stop, but it did.