How to tell my dad I know he is a pothead?

I have known my dad smokes for a good year and a half. I always try to get him to admit it, like when he goes to the store* looking normal everyday, just to get a few things and comes back hours layer with bloodshot eyes talking all slow and stoner like and reaks of pot. I usually ask what took so long and he always comes up with some super intricate story about some crazy shot that happened to him, but I know better. I have also found a pipe, which was on the side door of the car when I was driving. And no I wasn't snooping, my dad had lost his wallet and asked me to check on the side door. Literally a second later I was feeling the bowl of the pipe when my dad told me to stop looking in a real loud serious voice, so I never saw the pipe but when I parked the car he stayed outside to *continue searching for the wallet inside the car* afterwrdw tue only remand left of evasive of the pipe was a used pipe screen. I have also walked in on him and a rasta looking guy chilling in our apartment. He claimed that the gy was selling him a new car radio, even though tue gy left like a minute after I got home and there was a blunt roach in the ashtray. His habit is not a weekend thing or even a few times a week, he is stoned nearly 24/7. His eye drops are used up in like a week. It is so bad that when I didn't have any weed to smoke (back when I used to smoke) I could get ugh with the shake left on his bathroom counter. I also am constantly loaning him money for this and that that never gets paid back to me. And the worst part of it all is it's not the constantly smoking thing that bothers me the most, it's the lying about it and being irresponsible and driving on it and with pipes in the car. I mean what if I got pulled over that one time and was searched! I'm only 16 and this is really stressing me, so please don't say stupid things like mnd your business brat, because I bet you won't be saying that when he runs over some e you know while he is out getting high and driving around stoned. So pleas just tell me how to tell him I know and that I am not a flipping moron, cuz if you don't know someone smokes after all this, then u r a MORON!