If he's riding in a "fast group" then the weight savings will be worthwhile. You can do this with a used 20 year old aluminum frame. It doesn't take elite hardware to benefit from light weight.
If he's keeping up with the fast group already, he may not care (i.e. it's not worthwhile, to him)
I'm not saying you have to spend a lot of money. I'm saying people mostly don't do the obvious performance changes anyway, and for most riders it doesn't really matter (as they aren't doing anything competitive enough to need it).
I'm not saying you have to spend a lot of money. I'm saying people mostly don't do the obvious performance changes anyway, and for most riders it doesn't really matter (as they aren't doing anything competitive enough to need it).