I think show him some of the cool stuff that you’re able to run on your server and see if he finds it engaging. You can let him know that someone on Lemmy (me) was able to build a career in the tech sector by being entirely self taught. I only took a handful of college classes on a GED because some of my high school credits weren’t going to transfer when changing schools. I was able to go a long way on just hard work and personal interest.
Of course, this only worked out because I was genuinely passionate about the field. If he doesn’t find computers fun it’ll take a lot of hard work and I defer to suggestions from another poster who offered links.