Cutting off contact with elderly parent

I do understand how you must cut off contact completely with these narcissists, but what do you do when the narcissist is your old 82 year old father? This man is still going strong although it seems he is losing his marbles to some degree. He and his wife (his prisoner) had lived on my property in my guest house until he moved out in a raging huff 6 months ago because he couldn't get his way about something. This is the 2nd time he's slammed out in the 6 years he has lived at my place. Each time, he finds a new place to live and then in a few months decides he's not mad anymore and worms back into my life never apologizing, just pretending it never happened. I have had 2 years of therapy and this time I really want to be done, but am conflicted as to how responsible I should be for this mean old goat who is on his last legs. He does have some money and I do have one sister who has really stayed away for the most part but is now having regular contact with him from another state. I have had no contact with him for 6 months and it's been the best 6 months of my life. I am starting to breathe freely for the first time in my life. I am so conflicted though....I would love to (and really need to) just never see this hurtful evil monster again. What should I do? If he was younger, the no contact would not be a problem. It's his age that has me so conflicted. I am new here and on the road to recovery from a horrific life with 2 narcissistic parents and am so grateful for finding this website. My mother just died, so I have peace there now, but do not know how to deal with this awful man. I would appreciate any advice anyone has. Thanks.