Drug problem in the house.. What should i do ?

Stop focusing on what everyone else needs to do and focus on what you need to do. Your mom's bf is a two time loser and your mom is grown and responsible for her own choices including having an addict around her children. If your mom truly wanted him out, he would be out. You can't control their actions but you can control yours. If abuse, neglect or your brother is in danger, call authorities. At 23, you can move out on your own.