P.M.
Since I'm not clear about what tone or responses you interpret as "stern," I can't give you a decisive answer. (Everybody's "stern" is probably different.)
Different counselors, in my experience, have very different styles and different personalities. The question at the center of my evaluation would be; "How good a fit is this person with my son's style and personality?"
Some kids probably do well with a tough-love counselor. I would not, personally, nor would my daughter, or my grandson. So I'd probably look for a different professional. Good luck.