It is possible that he may need to wear a head halter for the rest of his life, but that's something you'll have to figure out as you go.
I wouldn't try walking him without the head halter unless he's responding to you without you having to actually use it (i.e., put tension on it to control his head). If/when he gets to that point, I'd just switch to a flat collar for v. brief walks and go from there.
I wouldn't try walking him without the head halter unless he's responding to you without you having to actually use it (i.e., put tension on it to control his head). If/when he gets to that point, I'd just switch to a flat collar for v. brief walks and go from there.