Peter, I had to bid my number one son a tearful goodbye when he was 22. It was for the usual reasons. I'd come back from a hard day's work and he'd still be in bed; and he'd stay there until dinner was ready. (I know, I shouldn't have cooked but I had two younger children and they needed feeding.) He still hasn't found a job that's 'right' for him and he's 42 this year.
Mince doesn't sound like that (or are you going to dish the dirt?). At least he's only with you half the week and he has a job, which is a rarity in this day and age.