If he genuinely can't concentrate on his education (perhaps for a medical reason), or he really has experience of menial work and thinks it's better, then maybe he's making the right choice.
But you should tell him, from someone who's experienced both, that education is much better than menial work, if you can do it. (Well I suppose that's just my opinion really...)
I suppose there are benefits, but how's he going to get a desirable partner on them (if he's not on them for a legitimate reason, or even otherwise, as sad as that might be).?