yes, it'll be fine... although he may not enjoy it.... after all, too much of anything can really suck, and codiene by it's self is pretty powerful, weed would only intensify it...

i'd reccomend him taking it one hit at a time and giving it time to kick in so he doesn't end up having a horrible experience with the two. but unless he has some real medical problems it doesn't pose a risk in and of it's self...

(this is of course assuming he really has been prescribed the medication and is taking it as the doctor told him to)