normally one tries 3 tiers.

1. reach; 2. match; 3. safe. compare your own stats with the class stats from those schools and pick the 3 tiers for yourself. then try to accept and enjoy whatever you ended up getting. :)

BTW, if your son likes engineering, Harvey Mudd or Colorado School of Mines are among some other choices. Thay are solid schools but less compatitive than Stanford.