If he was dependent on opiates, from the heroin use, then he is still dependent even if he switched to suboxone. You don't get a physical dependency to specific drugs like heroin or bupe.. you get dependent on opiates in general. So he's going to go through some withdrawal no matter what, the point of switching to something like bupe and tapering down to a low dose, then stopping, is to make the eventual withdrawals much less severe. So yes, if he was dependent from using the heroin, he'll still be dependent after taking the bupe, no matter how many days he takes it for. But as long as he was doing less bupe relative to his heroin tolerance, his withdrawals will be less severe. If he stops right now, it really wont be that bad. He'll feel shitty and uncomfortable, but it will be bearable.