My experience of friends and relatives who were dying is that some do regret things they never got round to, as they in the case of two who died long before they reached 70. is that They had thought they would have time in "the old age" that they never saw to do these things.
However, it is often a passing phase, if the person dying is able to come to terms with the fact that they actually are dying. And in the case of those in severe pain - may we all be spared!- the process of dying is something they want to be over and done with.
I myself have started sorting through the things I do not want anyone reading, discarding things that will be meaningless to others, if I cannot find anyone who would like them, and making up my mind about which of the more intangible things, like travelling somewhere I always have wanted to go to - is it still possible? Do I want to go there without my husband?
Some of it I probably will not do, some of it, I hope I will, but am unsure about, and some things I know I do not want to do on my own.