Deadbeat dad constantly gaslights my mom and the rest of my family

He’s been a manipulative bastard my entire life. My mom does nothing about it and just takes it, even when his actions directly affect the quality of life of everyone around hum. He hardly contributes anything to our household and uses all his money to gamble. (Sometimes other people’s money). He does not seek any desire to change and it’s getting more frustrating to deal with. One of these days I’m worried that he’s going to hurt my mom (he has that history..) while me and my brother aren’t there to keep him in check..