那你就拿这个来说他的AREA TO IMPROVE.

he has room to improve in problem solving skill, espectially when it takes multiple steps and it need ability to connecting dots to get to the next level in his career. 

I think assigning a mentor to him might be helpful.  (这里看你自己想不想。想的话，自荐一下，你就成他领导了。再把自己手中的活推掉一些。因为你要花时间照顾他。）