Sorry-have to disagree with you in part. 3-D planes have very lite wing loading, fly very slow and stable and in some cases are much easier to fly than some trainers. They don't have the dihedral for self correction but if he has some experiance and success at landing Trainers and Low wing craft, try it but use your head. Set on low rates, they are as gental to fly as a Kadet LT40.
If you have no high wing experiance-forget any low wing plane for now. I agree on War birds with high wing loading, you'll need lots of flights before attempting that.