A dog I'm sitting isn't eating their food. He sniffs it but just walks away. He isnt free fed and gets fed two times a day. He drinks water fine but not his food. I'm at a loss of what to do.
I wouldn't worry about it too much. Dogs frequently lose interest in their food in a new environment or seem to go on a hunger strike. The dog isn't going to starve. In fact, when the dog is hungry enough, he will eat. You can try adding some broth (low sodium) or other tempting food to his food. But they all eventually do get back on their feeding schedule.
Very normal. Also, most dog owners are aware that their dog probably won't eat as well while in a new place. So I would mention it to them and ask for tips. I have found that it works well to feed them in a bath or laundry room. Someplace small with few distractions and 10 to 15 min of alone time.