Also - your mother is a grown adult human being. If she gets into trouble financially, it is no one else's responsbility to bail her out. I assume this is something that hasn't just started, the spending more money than she makes, so she does have the ability to see if you spend more than you make, eventually you will end up in the hole. She knows she has to pay rent/mortgage, bills, etc. If she ends up in the street that is sad but it is not your or your sibling's responsibility to keep her from the street, because if she ends up there she does so because of repeated bad choices. If she wants help, she can ask for help and you can decide at that point whether or not to help.

Swooping in to keep her afloat without her asking is enabling behavior, and codependent. Are there alcoholics in the family? Both of my parents are Adult children of alcoholics so I found that the behavior carried on down to me and my sister even though neither of my parents drank.