A lifetime razor for a newbie? I can't say that I have tried a bunch of high-end razors, but when I read the OP's post, immediately the Henson AL13 Mild popped into my head. Super easy to use, gets the job done, can last a lifetime, and you can get it even lower than list if you can catch one of Razor Emporium's sales. I've had fewer than 10 razors (I've lost count), and now my only 2 razors are a Henson AL13 Mild and a pre-war Gillette Tech. I do love the Gillette Tech, but 90% of the time I reach for the Henson. I really could see myself still using this, and only this, razor ten years from now.
I don’t know, I think @mikhou’s suggestion could be spot on. Sure, he may not like whatever razor he gets, but if the OP indicated that the budget is low 3-digits, then surely a $70 razor isn’t out of bounds.The teenaged nephew might not like the razor and would have zero interest in keeping it for a lifetime. A used vintage razor probably is the way to go.
I say “could” because I don’t know if the nephew would be into vintage or not. For modern, he’d be hard-pressed to do better than a Henson, though there are other good suggestions in this thread too (so long as it’s mild or mild-ish, he IS a newbie after all).
Probably not a lot of teenagers are into vintage things. If he is, that’s great, and I’m probably the wrong person to advise, though the birth year idea above is good. If not the nephew’s own, then maybe the OP’s father / nephew’s grandfather’s birth year might be meaningful.