Marijuana, wax

My fiancé has been lying about smoking pot. I found out that he’s smoking pot and wax. I don’t know much about it all but I’m so beyond pissed. Our son is 8 months old. If we don’t resolve this will I get full custody from him smoking it?

Edit-

He comes home from work and spends about 10 mins with our son then sleeps all night long. Doesn’t help do anything. And when the baby cries he gets very irritated with him.

I’m not saying I’m totally against pot. It’s just the lying he’s done about it and the fact that it has changed the way he acts. He’s very irritable, sleepy and manipulates everyone. I don’t know what to do.

He is 22. He has a cpl and has already been in trouble once.

I’m not trying to take my son away from his dad but his dad really does nothing to take care of him since he’s always sleeping and annoyed by the baby when he cries or spits up.

Thank you all for your help.