You don't know the full facts of his situation and you're not sure if he's being straight with you.
If he's on formal probation, which I'm sure he is if he's a convicted drug dealer, he has a probation officer. At a bare minimum, he can always contact the probation department for a copy of his paperwork and to clarify the terms of his probation.
You would expect his probation officer to intervene in a police investigation? To what end?

