What does he mean by structural engineering?

Buildings or bridges?

Structural engineers do high end design work for things like stadiums, high rises, large bridges, etc. One of our PM's dad has done many of the famous structures in the US. He is a bit strange, but brilliant.

I took him and the PM to a stadium for a major playoff game - and he just stared at the trusswork, then said, "I did this design in 1969." He'd forgotten what it was FOR, but recalled the relationships among the members. This was back in the days of graph paper and slide rules!!

Look up "Finite Element Analysis" and "Mechanics of Materials" and "Statics" - these are the base fields for structural engineers. A guy named Timoshenko is the father of much of it.

http://en.wikipedia.org/wiki/Stephen_Timoshenko

You can also look around for engineering competitions at the local college and go to them. That will tell you more.

If he has a real interest, when he turns 16, look around for an engineering firm who would take him on as an intern. I worked for a chemical process design firm when I was 16 and 17 doing programming - so it can be done.