You could say something along the lines of:
"Hey, Friend, what's so good about weed? Why are you always smoking it?"
If he's smoking it for medical purposes, then just drop it, but if it's illegal and he's doing it to "look cool", then I would further ask questions about it.
Answer:
Fracture.
Explanation:
In the index the main term to reference is fracture.
Answer:
Blurred vision and heart disease blocked blood vessel
Explanation:
Sickle cells can block tiny blood vessels that supply the eyes. Over time, this can lead to blurred vision (and sometimes blindness).