Elaborating on the downhill point a little more, remember that it takes far less energy to go 10 sec/mile faster on a downhill than to go 10 sec/mile faster on an uphill, as long as your musculature can handle it.
Seems like a good strategy would be for him to surge a little on every downhill - he would get a "free" couple of seconds every mile since he can be confident that his quads will hold up.