Okay, so he's getting $450 per month to buy the gasoline to drive to and from his appointments. He is getting his rooms covered when he has to stay in one area to take care of several things.
You are upset because he is eating out every meal during the time he is not at home? Right? I think that he can choose how he eats when he's out.
He could eat off the dollar menu at Mcdonalds. If his room has a mini fridge he can buy fruit and fresh veggies at Walmart and keep them on hand to fill out the menu and to snack on. He can eat a granola bar and an apple for breakfast instead of an egg McMuffin at McDonalds...just some ways I save money on meals when we travel.
I can feed my family of 4 at McDonalds for less than $20 ($17-$18) and get the kids Big Kids Happy Meals.
I also have bananas and other fresh fruit in the room. We hardly ever spend much on food eating out.
You are not spending that money on him in your home budget either, so you should not be spending that much money while he's gone. If he was at home he'd be eating too. It may be costing you more in the long run but he needs to be smart about what he's spending too.
I think that they told him when he took the job what he would be getting. It's up to him to spend less than they are giving him. If he took the job agreeing to those terms then he needs to suck it up if they refuse to look at his expenses.
I have had friends who traveled for work and they flew them there, put them in hotels, paid each meal at the restaurant of their choice, also paid for prostitutes, and paid them overtime for anything over the regular 40 hours they worked. My friend was very happy her husband chose to not select one of the ladies that showed up the first evening at the company's request to "take care of the guys".
The reason so many companies are implementing pay scales like this is that they get taken advantage of. For instance, someone mentioned Filet Mignon. He could eat out every meal like that and just turn in an expense voucher at the end of every trip. They would be stuck with it. Or would stick it to him. This way he eats what he wants when he wants and is in control of how much he spends.
Part of this expense is on him and part of it is on them.