What does the bible say about helping or not helping a person who won't help himself?

In your specific case, I think you have to look out for the safety of your family first and foremost and having him there doesn't sound like a safe decision for your family.

But to answer your header question, I can give you some specific verses about giving, but nowhere does it say that we have responsibility for what others do with what we give them. Nowhere does it say give . . . if the person is going to do good, if the person has a family, if the person is a christian, etc. It just says give.
God has made me a steward of my money, I am to give according to what he has given to me, not to make an account of what the people I give to do with that money.

That said, I do only give to causes I support and believe in simply because I want to further their work and I think it's smarter to "teach a man to fish, rather than give him a fish"

Do you really need a Bible verse to do what is right? He needs help, and if you can't give it to him at least help him otherwise....find him a rehab, counseling anything but don't turn your back....

older you need to realize there is a difference between helping and enabling. Refusing to let someone move in with you who is a drug user, doesn't respect the house, and lazy is responsible. At 25 years old he shouldn't need his hand held to find counseling or rehab. If he wants to do that I can guarantee he already knows how.

purple, addicts need an extra push, or else they don't have a problem....

Exactly-and sometimes that "push" is stopping the enabling so that the addict hits their rock bottom. Here's another way to look at it-unless a person is extremely well-to-do or wealthy, the average person, especially in this economy, cannot afford to be taken advantage of. It's all most of us can do just to keep our heads above water.

He needs tough love. My brother is a recovered alcoholic. I finally got tough and told him I wasn't picking him up after a call from him when he was drunk. He called a pastor who was a friend, and knew of a rehab/Christian place in Boone NC. MY BROTHER is a PASTOR now. He's a miracle. Seriously, I consider it a miracle. I'm so happy, and proud of him. He stayed at the place the required time and then 4 more months.

Throweth the bum out ~ Genesis 1:1

ignorance

seek help for him dont feel bad