The way people are hiring these days it won't matter if he was 200 or 300 pounds. A great goal for him would be to try and become healthier through diet and excercise, once he gets a job and is on the road a lot his bad habbits will only be compounded. That and the personal satisfaction, better look and self esteem boost can't hurt for the interview and would probably be a great topic for a HR question "what was the hardest thing you've overcome?"