A 1/2 ton uses the same springs as a 3/4 ton in front and the whole axle from a 1/2 ton will fit and disc brakes are available. But of course that will leave him with 6 hole in front and 8 in back. A 55 and later half ton complete rear axle will fit in the rear with very little modification. If he is going to disc brakes, I wouldn't think he would mind 6 hole wheels all the way around.