That is great Dave. Priceless time he will remember forever. Be sure and instill your appreciation for GSF in him. Our club is pretty small and needs all the members it can get.
A snorkel gets ineffective below about a foot. Lungs can't breath in below that depth much (because of the water pressure exerted on them) and if they can you just exchange old air in any longer length tube so get no new O2 and lots of CO2. So below about a couple feet, it is all up to breath holding and free diving. The snorkel just lets you breath easily while resting on the surface. Once upon a time I could free dive to 50'. Don't even try any more, although since I have lost about 90# I think I might be able to make it 2/3 that far.
