The Fifth browser really makes it apparent how much junk you are downloading - which for me is super important as I'm on a limited cellphone data plan for my internet needs - by choice. But that's not the main reason I'm using TinyCore, but sure is convenient.
Thing is, know your audience. Perhaps a turn-key Chromebook would suit his needs better, and when he outgrows it, you can put it into dev-mode, and do what I'm about to do:
Put TC on an Asus M004U ChromeBOX. Here we go .....