Computers yes if he has a head for it but otherwise plumbing sparky chippy. Work for someone get the experience then go self employed if he feels that’s for him.
No way would I advise anyone to do this job BUT starting now his expectations would be different to mine after 47 years. Who knows it might be right for him and whatever happens it would be a job for life-there will always be a need for drivers in the foreseeable future.