I am surprised by the replies of the parents on here who state that they either offered no advice, or told their children to find something they loved with little or no guidance. We watched our children at home and at school from an early age, and tried to evaluate what they were interested in doing and learning about and then tried to suggest fields that would integrate with those interests. We encouraged them to make the most of the courses in their areas of interest, but to also take challenging courses in other areas to make them well rounded. We also helped them identify the general field that they wanted to pursue in college, because its too expensive to just go to college without an end goal (although I do think the college experience is a great advantage in the maturation process). However, college is not for everyone and technical trades are great for some.
I would suggest you talk to your child about his interests. Does he do well in STEM courses, the arts, or the softer sciences? Does he want to have a lot of exposure to the public or work in a field with little interaction?What were his interests since childhood, did he build, or paint, or pretend to teach? All these are hints into what area might be a good career fit. Everyone wants to make a decent living or better, but working at a job that is drudgery can be stifling. Thankfully we were able to guide our children to careers that they love.