No i have a very laborous job myself and i still hit back and legs the hardest.You have to remember your legs equal up to 1/2 you body almost they can take alot of punishment same goes for your back its the biggest muscle group on your upper body.I have found you have to cycle your training in these types of jobs during the seasons.In the winter it will be easier to put size on then in the summer b/c of the liquid consumption we have to do to be hydrated.You should have him on 50%carbs/45%protein and 5%fats.If that still doesn t work which i highly doubt that it won t.You can put him on my secret recipe bulking shake(not a secret anymore lol)you take a 1 liter cup 4 scoops of ice cream, 2 scoops of muscle milks cyto gainer and fill about half way with whole milk and blend.Drink this before bed and you will put the lbs on.