I used to build guitar amps for fun and repair them for friends. I have parts of a Sound City, Plush, Harmony, Gibson amps in my storage unit. I have some old heathkit thing from the 60s. I have two different Traynors.

Depending on your budget, I'd get a Vox Pathfinder, AC4, or AC10, and then take him to get a pedal or two after Christmas. You can usually find an AC4 used easily. Some of the digital amps are fun, but if he really gets into it, he's more likely to keep one of the amps I mentioned and buy pedals anyway. An AC4 (especially an AC10) will be something which usually sounds really good on it's own.