Samantha,

There is a reason why the phrase “tough love” and the word “enabling” exist.

There is the fear of “what if” if you or your mother don’t do things for your brother but can you really predict if that is really the best for him?  Making decisions out of fear is not the best approach in making the best decisions.

You cannot control your mother and my guess is that she would rather enable his irresponsible behavior than kick him out.

It is painful to stand by and witness your mum doing things that are not good for her financially (and emotionally).  I am highly doubtful that you can influence any change with her or your brother.

No real useful advice here.  I believe that the only person I can control is oneself.