In the current climate, he might have a shot at getting hired at a lower-tier regional. But his long-term prospects would be poor, because he would have a very low odds of getting on with a major, and high odds of medical disqualification down the road.

Should your friend interview now or try to to lose weight first? He might be able to get on with a regional now and then lose weight over time. The problem is that if he has preferred employers, he might poison the well with them forever by showing up overweight, thereby limiting his future options.

I would suggest making weight loss and fitness a priority...do a permanent lifestyle change now. If your friend is serious about this career, the social, self-esteem, and health benefits will be well worth it. If he is really pre-dispposed to putting on the weight, he might want to take up an endurance sport to keep the weight off for life (biking, running, rowing, etc). This works for me...I like to eat, so I just have to work out a lot.