I'll try and help you out a bit bro.
He needs to make sure he is eating frequently and staying hydrated. His appetite would increase naturally since he is on his feet all day and active. It would be a good idea to buy an MRP w/ casein as it's protein source and low glycemic high fiber carbs, so Omega 3,6,9's and MCT oil would help slow down the digestion and keep him anabolic. I like to make my own MRP for work and bring a shaker. Just blend up 1 1/2 cups of oats (dry) so to make it into a flour/powder. Or you can just buy some brown rice flour, barley four, rye flour, whole wheat flour, anything high in fiber (the rye may be a little too high in fiber and give him the shits) Whatever you choose...... put the flour/powder in a ziplock w/ 50g protein preferably a mix w/ main ingredient of casein. Cytosports evopro is a good choice, and tastes damn good. Buy some Omega and MCT oils. If not.....canola will do. You can throw some glutamine in the mix too if you want. It gets expensive though.
So........50g slow digesting protein
75g low GI high fiber carbs
14g healthy fats (1 tbs of most oils)
5-10g glutamine
Assuming he gets a good breakfast this would be good to time it about 2.5 hours before lunch (12:00) and again 2.5 hours after lunch, then hopefully he can get his hands on some whole food @5:00.
let me know if this helps. Later bro