Now Bill, why encourage him like this? Don't you know that the Zuiko glass will poison his photographic vision and he won't be able to ever use a modern zoom on some modern body ever again?
Seriously, my recommended Zuikos are the 24/2.8, 35/2.8, 50/3.5, 100/2.8 and 200/4. These are all very affordable and produce exceptional results. Best bang for the buck and they don't take up much space in the bag. I've got two OM bodies, (one with a winder mounted on it) and these listed lenses all in a SMALL LowePro Elite III bag with room for filters, film, and other miscellaneous items.
Of course, he DOES need to get an OM-4Ti, but that's for another day.