I can very much relate to your situation. I think the fear of being without money can be such a factor at times, that people would sacrifice other things that shouldn't be sacrificed. One example is my mother, she is abusive to me. But was severely abused as a child, and does not have very good boundaries. Several years ago, she started a relationship with a married man who was sending her money. I caught on to the abusive and controlling aspect of what she was doing, and tried to get her to stop. But she didn't know how to survive without the money. Finally she did get out of that relationship. And it was scary for her.
So that is my take on this, it is not only stress. But usually people stay in an abusive relationship because the person considers something to be more important than self worth. In my case, I was just damned scared of being left alone. When my ex kicked me out suddenly, I had no choice but to see in the dangerous position I was in. I think this was very traumatic for me, and one of the biggest traumatzing aspect was that I was forced to leave my children in the timeframe of 10 minutes. I think if I had the chance to think through it, and discuss the best solution, things would have been a lot different. That time, I didn't have.
In your case, it may not make sense to compare. Because physical danger, is what it is. But also, you mentioned your sister. And I can consider this to be a very important concern of yours.