How do I get a recently-adopted shelter dog to start eating?

The dog is a male Silky Terrier, about 1 year old, and he's a nervous dog. I've tried to get him to eat, because the shelter worker said that he'd been transported for a couple days, eating whatever donations that were given to the dogs on the truck, and that he should gain at least a pound. I've tried giving him mostly dry food, but I've tried putting water in it in case the food was too hard, I've tried putting dog treats in with the food, I've even tried giving him the food by hand (he just basically spat it out)... He's not at all reclusive, even though we've only had him a little over a day, though I think he may have been abused by a man, cared for by a woman, or both before we adopted him, because he always wants to be around my mother, and never around anyone else. But my family wants this dog to be primarily mine, so I'm to be the one to feed him and take care of him. Help?