I agree, if he is using an excluder that is his problem.
Bees will not drawn foundation, even wax, above an excluder.
If he is not using an excluder, I would suggest moving one of the frames down to the middle of the brood nest, and let them draw it out and the queen lay some eggs in it. Then move it up into the medium super. Sort of like a bait frame. Yes they might build drone comb on the bottom of it, but think of it as varroa control, and just cut it off when moving it up.