HELP!! I think my cousin is a meth head?

I seriously think my cousin is a meth head. He is always talk about how “cooking” is his favourite amusement, and then he nudges at me like in that monty python skit. And I have seen his kitchen. A stack of empty pizza boxes does not qualify as “food cooking”. His teeth is not only such a horrid thing to see, but also to think about. Yellow, crooked, and rotten. I am afraid to ask him if he is indeed a meth addict, because he yells a lot and he always look angry and constipated. Please help me, I’d hate to see another relative die, and I want to help him.