What would you do in this situation?

[duckfool]

i would be like, "Dad, i found some pot and rolling papers in your drawer when i was looking for __________ in your room." (fill in the blank) and then see what he says. DO NOT MENTION IT WAS YOURS! unless he says it is. then discuss it w/ him. that's what i'd do i guess.

pricisely. Doing anything else other than that will almost certainly create a bad situation for both you and him.