Get him what he wants and a keepsake, perhaps? A present that he grows to love might seem a bit poo at 18.
One of the best “keeper” gifts I ever received was a leaving present from my first job. It was a high-end Swiss Army Knife, big lump of a thing with all the screwdrivers and bottle openers and tools for removing boy scouts from horses’ hooves and all that jazz.
At the time I thought, “that’s a nice novelty but I’ll probably never use it” but it’s been either on my person or not far away for the best part of two decades, used day in and day out and taken a battering, and it’s still works as well as it did when I got it. Annoyingly, I finally lost it last year, gutted. The Best Man at my wedding bought me a replacement as a wedding gift, and that’s now taken the place of the old one at my side.
So, yeah. Point is, I didn’t initially understand the value in what I’d been gifted. So maybe get him the phone, and also give him a SAK or a wallet or something else likely to build sentimental value.