Ask HN: What do you do if your parents keep asking for money

So quick explanation, I'm a relatively young engineer, i'm also single and have moved up quickly (positionally and in salary) career-wise and my parents have been around to notice. At a certain point, I started making more than my parents. When that happened, my father asked for some financial support claiming that he was barely making ends meet (which had happened in the past when I was younger). He wanted me to send him $1000 monthly for what he initially said would just be 8 months. However, I kept making more money and he kept asking for the $1000 every month (the last tally i have is around 32 months). This went on to a point where they also asked for a house and really pressured me into buying one. At the end of the year, it ends up being a good sum of money that I give to then entirely tax-free on their end.

About a year ago, I left to go work on a startup as a cofounder. We bootstrapped the whole thing so there was no income other than money I had saved up so I stopped sending my parents the money and they understandably stopped asking for it. The company I bootstrapped didn't work out so I'm again jumping back into the workforce and getting paid around what I was previously making and my parents are once again asking for money saying that they really need it (father works btw).

I know I'm well payed but I work very hard at what I do; but then again, its my parents that I'm helping and after all, I'm single and have no other obligations to take care of than myself. I'd feel extremely guilty if I didn't send them money and just kept it for myself. So my question is, has anyone else been in a similar situation and if so how did you handle it? what should I do?