There are Tons of Tool companies out there, Many that would stand the test of time till it comes time for your son to use them... With that said Up untill MetalsRecycling issue, Ive NEVER once read a thread here about Snap on not warranting a tool because of not being the "Original Purchaser". I suspect i have read about 1000 denied Warranty threads from a Multitude of Brands but never based on Ownership.
Bear in mind though, Most of these tool companies carry this special message in there warranty clause, Below you will find Matco's.
Matco.
All products sold by Matco to its Distributors are assigned a warranty code in the Matco Price List. The limited warranty provision with respect to each such product shall be the limited warranty designated in this warranty code agreement and may be amended by Matco from time to time in its sole discretion.
Id say the best thing you can do is teach your Son how to properly use tools and identify which is the Best tool for the Job, I was fortunate enough to have a Very wise grandfather who taught me the difference between the Right way and the Wrong way. Yeah.. I still make mistakes today but as long as you learn from your mistakes, your heading in the right direction. Have fun building your sons collection..