Well, he could start out by getting a PPL and see what flying is all about.
FWIW, personally I think being an engineer is more intellectually rewarding and better return for the money. If he were to pursue this path, he would end up with a better all-around appreciation of the industry and with the means to fund any CPL training he might wish to take without putting any undue strain on the family finances. He would also have a transferrable skill.
Other than that, I would suggest to get in touch with your local aviation community and listen to what they say. btw, mostly everyone appreciates a hand with washing the planes/passing the tools/tidying up the workshop... if I were a 16 y.o. with an interest in aviation, I know were I would be
Crossed posts with UAV--same gist