FOR FUCK'S SAKE, do not give away your car. Assuming it's actually your car with your name on the title, it's yours and you owe it to no one. If you give up your car, you essentially gave them money and a car. You never should've given them a dime in the first place. He's making over 5 grand a month, which should easily support a two person household.
All you've done, is enable her to continue to fleece your brother for a longer amount of time. Let them fail, let them struggle. It might seem harsh, but they're not gonna change if people around them prop them up and let them get away with this shit.
Basically, quit giving out money, especially when your income seems to currently be 0 and do not give up your car. I feel like you've gotten slightly better over time with this, but you really do need to get away from your family for a while.
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