My SIL has a low paying job and is currently largely supported by my MIL. SIL makes a whole host of poor financial choices (expensive car, CC debt, expensive pet, smoking, general money wasting on stupid crap at Walmart that she doesn't need, fancy phone). When MIL dies, SIL will probably quickly run through her inheritance and then come to us.
She truly is low income, but at the same time, if she made good choices she would be fine (especially as she has a safety net, unlike those in generational poverty.) But, luckily H realizes after seeing the pattern of SIL's behaviors for the last 10+ years, no amount of money will help. If we give to help with this month's crisis, there will be another one next month. So we will not be falling down that rabbit hole. If we ever help it will be with strings attached (sitting down with us and going over the whole budget, making cuts) that SIL likely won't accept unless things are truly dire.
So far she hasn't outright asked us for money (MIL fills that role!) but during her divorce she called DH A LOT and did a lot of not-so-subtle testing of the waters. "Brother, I have no money, I need this much money, how am I ever going to get it, woe is me woe is me..........long pause..........". H responded with lots of ideas like: sell your car, cut your cell phone, would you like me to go over your spending with you? She passed on that, not surprisingly.