I wouldn't take it to a lab - I used to work in a lab. That's not a good idea. If it's illegal, just having it in your possession is grounds for a criminal charge.
All you can do is ask him. I think if I was the homeowner/parent, I would dispose of it first and ask questions later. I would want it out of my house. He could have a medical condition, and if that is it and he hasn't told you, he'll have a prescription he can show.