Wow.
He's an adult who takes no financial responsibility for his child.
Sounds like when he works his money goes to the junk and gas to acquire it.
He does not sustain employment and it's always someone else's fault.
He does not financially sustain himself and so you, his mom and grandma do it for him.
What reason does he have to contemplate take responsibility for himself and his own addiction so long as there are people around ready, willing and able to do for him, what he can do for himself?
Your child deserves to live in a home that is not compromized by another big ole baby and his addiction/lifestyle.