I did a 5 year apprenticeship as an Electrician ...now they do it in about a year and the the would be electricians are next to useless. What with new reulations, Part P etc the whole thing is a nightmare. Avoid being an electrician like the plague.
Anyway if Maths & science isn't his thing then electrical engineering or computers is a no no. Anything interesting in computers is now done in India for rupees and there is no engineering industry here....so stay clear of engineering.
Probably best to go into Management/ business of some sort or Law.