This seems bass-ackwards.
How about we just drain his bank account because we are afraid that he is going to spend his money on illegal drugs.
Once he proves that he wasn't going to do that, after due process, then he can have his funds back again.
No one who has had their guns confiscated under a Red Flag Law, will ever get their guns back again. The guns will end up in an alley for gang bangers to use on each other.