Both my parents and my in-laws did A LOT for me when I grew up. My wife's parents practically sacrificed their whole lives for her and her brother. If they need help, I'll give it, as plentiful as I can spare, and she knows it. We're open about this and I am open to the idea of her mother coming to stay with us if she needs to. She currently gets a measly salary and has practically no pension, so in 10~15 years she might have nothing to live with, of or off, and that's most probably when support from our side will kick in. I'm preparing for this and for my own future though so that I will hopefully never sit in that boat. The cycle needs to be broken, and soon.
As a PS: It's surprising to see how many "rich privileged white people" still have struggling parents (like, REALLY struggling). My grandparents have nothing but a state pension, my inlaws the same. My own parents luckily have a good future ahead, as soon as my dad retires he will have a solid pension. I want the same. The cycle of kids having to support their parents have to stop, and I hope to stop it in my lifetime. When I retire I don't want to be dependent on anyone or anything.