First of all, does an adult child owe anything to its biological parent? I don't do all or nothing black or white thinking, so the answer is, always, "it depends" on the people and situation. In your case, I don't know enough information to have an opinion. But if this person is for sure solely responsible for your PTSD as in they harmed you, then I feel that not only do you owe them less than nothing, it's also your right to decide. We're all going to die. Having a terminal illness doesn't make someone "special" because life is in itself terminal. So I don't see you as having to do anything at all.
Personally, I don't expect anything from my kids, and when they are older I will tell them this. They can put me anywhere if I go off the rails. Life is my gift to them. I want them to have a good life, totally unlike mine. That is all I can do to make up for my suffering. I have PTSD, so I'm not the ideal mother, but, daily, I endeavor to provide them with the best life I can give them with support, education, fun, exploration, love, hugs, reflections of beauty, creativity, dignity, respect, and the American freedom that many have died and suffered for. I suffered, and my only desire is for them to be as happy and free from misery as possible, almost to live the life I can never have. Most of all, I want them to be free and respected to make their own way in life, not to live for me. They owe me nothing. They are the greatest gift life has to offer me, and I love them more than I love myself. How could I expect anything from them?
I realize this is not a popular or warm fuzzy way of viewing family. But, in the scope of how our culture has shifted, in which the most important years of a child's life, 3 months to 5 years, in North America is now outsourced to the lowest educated strangers, I wonder if that generation will feel responsible to "repay" something that wasn't fully given. I don't know, but when it comes to abusive or abandoning or negligent parents who did real and lasting harm, who have not apologized, or even admitted it, I say, "don't throw your pearls to swine."
There are good people, young people, the hope of our world, who really deserve our time and energy. The dying deserve basic dignity and civility, no matter what they've done, but it doesn't have to come from YOU. YOUR compassionate gifts to the world should go to the best possible recipients.
A woman I am close to told me that it fell to her to relocate her sexually abusive grandfather to a home, and she took care of all his arrangements. Even doing that, you should see her face when she says it, like she's going to be sick, feels terribly wrong to her. She did it out of duty, but she gained no self respect from it. I think it was a bad idea. A social worker or someone paid to do it should have done it. I don't think her doing all the packing, caring for him, bathing him, feeding him and moving him, was right. He didn't deserve it, and she knows it. It was wrong on so many deep levels. It did not earn her heavenly halos; dark circles form under her eyes when she speaks of it. The anger and resentments only increased. Don't feed the demons.
As POA, you can delegate all her care, and I suggest that you pass the buck.
