There is no such thing as overkill. Dead is dead.

Honestly any of the regular factory loads will give him what he wants with out the hassle of trying to find possibly scarce ammo. Let him hunt with it and just use a load that the gun and the shooter shoot well.

If you still want lower velocity loads Remington makes a managed recoil load with 150 grain core lokts and is loaded 'down' to about 2650fps but why bother cause this is much more gun than is needed on deer also. But like I said it will not be available everywhere like the standard stuff is.