But the thing is that he will not have "nothing". He will be provided for in old age: by you.

If you supported him until now, then why would he worry about you stopping it? He doesn't need to pay mortgage or utilities or food because you pay for everything. If my husband decides to not pay his share (wouldn't happen but hypothetically), he'd be on a street like tomorrow. I wouldn't pay full share of household bills alone if he is living with me rent free.

But your husband knows that it won't happen. He is lazy (and is an addict and wouldn't seek help)but since you enable him, he has no needs to try.

So when you ask why is he not working, the answer is because he doesn't have to. He is being supported by you. Heck he even gets to drink vodka for free!