They do not "pick on" people, as in make fun of them. There is just interaction between the servers and the guests that is really entertaining.
For example, at the 50s Prime Time you feel like you are actually eating in a 1950s home (the tables, decor, etc) and it is pretty authentic. The servers contribute to this atmospher by simply "acting" as though you are a family member and they are serving you a meal--like Mom. They might praise you for cleaning your plate, for example. It's actually very funny. We enjoyed the entire experience. Children would especially like this place.
I would tell your DH to go with an open mind and see what happens. I think even a shy person or one who generally doesn't like to participate might actually have a good time. The food is actually very good and has a homemade taste to go along with the theming.
I don't know about Whispering Canyon. I have heard it is noisy and lots of little kids, so probably this wouldn't be a good bet (although I can't wait to take my son there!)