If he's not ISFj, INTp would be the next possibility... but it seems unlikely. His mom read the descriptions and picked ISFj (without any coercion lol). He's not "timid" or laid back enough to be an INTp (not sure how to word that better... may need to describe this "INTp timidness" elsewhere if it's disputed, and the laid back thing is obviously a matter of perception because some people see INTps as bitching about everything all the time), and the most apparent thing about his type is the IJ temperament. And Ne makes the most sense for his PoLR. He uses Fe a lot less than most ISFjs probably do, but it's not a sensitive spot. He can certainly take Fe criticism in stride.