my first piece of advice is to find out whether he really wants to replace them or not. knives aren't like clothes or cars ... they don't wear out or lose style. i've got a 30-year-old wusthoff chefs knife and i wouldn't dream of replacing it. if they've been damaged over time, or something like that, that's another matter.
His chef's knife is really worn down. Its almost the size of a 6" chef knife from 20 years of sharpening.