I don't know what level is required for conviction like is for alcohol.
This comment tells me that your statement that you "know all the details . . . about what he law is regarding alcohol" is wrong.
In order to be convicted for DUI, the state must prove that the driver was (a) operating a motor vehicle on a public street, and (b) was impaired because of alcohol or drugs. In no circumstance is any particular "level" "required for [a] conviction."
Rather, if a driver has a 0.08% blood
alcohol concentration, impairment is presumed.
However, having a 0.08% BAC is
not required, and a conviction can result for any BAC over 0.0% if it can be proven that the driver's ability to operate the vehicle was impaired. Obviously, a BAC makes no sense with anything other than alcohol, and a conviction can obtain as long as it can be proven that the driver's ability to operate the vehicle was impaired.
How about this: "Hey dumbass. Howzabout not driving when you've been smoking pot?!" That seems like a pretty smart thing to tell him, don'tcha think? As far as the charge, your friend should consider retaining an attorney (especially if a conviction would impact employment or eligibility for student loans).
I think he believes that since it's legal elsewhere it shouldn't have been a big deal in New York to be under the influence of marijuana and it's just like an infraction.
If, in fact, he thinks this, then he's an even bigger idiot. Alcohol is everywhere, but it's completely
illegal everywhere to driver under the influence. If he had been standing around on a street corner under the influence of pot, it probably wouldn't have been a big deal. However, when he chose to get behind the wheel or a car, it became a big deal.