I'm not sure what advice your friend wants.

Regarding their job, no one can make the brother help. He has the freedom of choice and can say no. Almost every son and daughter if they can will help parents tht they have a good relationship with but not always will they help their siblings, that is far more complicated and it doesn't sound like the probably have a good relationship as siblings. Not much you can say or do about this.

As for finances all they can do is try to find another job or get unemployment if it's available til they do so. I'm not sure what to say about that

I'm sorry I don't have better or some advice but sometimes all you can do is be a good listener for friends.