It seems as though he doesn't know that he's scared of them, but when doing them it's obvious that he is.
I wonder if that's the key. It's quite hard to deal with a problem if you don't know you've got one.
FWIW, I became scared of stalls early on in training after doing rather a lot of them with a gungho young instructor and ending up feeling ill. I got my PPL, did a few stalls when more or less forced to on the occasional checkride, but NEVER on my own or if I didn't have to. Then after a few years and lots of flying I decided I ought to do spin recovery training. I put it off until I found a very experienced instructor that I trusted, and explained that I was scared even of stalls, tended to get airsick mainly due to nerves, but I wanted to do it. Well, it took two sessions (mainly because I felt ill quite early on), with a lot of patience on his part, but I finally almost enjoyed it. And I think it helped that my instructor never got upset, kept totally calm throughout (I was nervous enough for two!), was totally non-critical, and was happy to do it to my timescale however long it took. So all I had to cope with were my own fears and weak stomach, not anything going on with him.
I know that doesn't give you any definite answers but I just thought it might help a bit.