R.J.
Here is the thing when she is broke and they take her house because she cant afford it and she needs care because she cant take care of herself ALL of that somehow comes back to the kids.
I have watched my MIL struggle with her parents like this for years, they were financially irresponsible, their house was foreclosed, their car repossessed and they couldn't for the life of them get it together. They were in their late 70's . Had she known sooner she could have stopped it. When they died she ended up with all the bills, burial, plot, funeral it left a really bitter taste.
Talk to your mother now let her know that if she doesnt get it together now and act responsibly now when something happens- and it will- that you will not take responsibility for it