I’m not one to be obsessed with dress / suit sizes, but I think a fair question to ask is, “is he / she within 10% of her / his size” (plus or minus, but divulging the actual number should not be done).
If bochur is topping 200+lbs, and his waistline is bigger than his chest diameter, I see no reason why he (or mom) should feel the need to ask for someone who does work on maintaining a healthy figure (I picked the boy and his mother as the chubby example, as the girls are usually in line)