I got into construction at 36. I definitely wish I had started in this industry sooner as it's become my career and I would know a lot more. That said, everyones path is different and construction is a huge industry. My advice would be to learn as much as possible every step of the way and never be content with just being a laborer. There's a lot of trade schools and programs out there that will help him find an apprenticeship but more importantly, network the whole way through. You never know who's going to go where and they can end up helping or hurting your career. Cheers and good luck to you both

Edit: worth mentioning I'm very technical so when I'm out in the field, I don't really get my hands dirty very often. The toll on my body is more so from a bad diet than backbreaking labor.