A vet once suggested that we give our sick puppy white rice, completely plain cooked white rice and after 24 hour of not throwing it up then you can add lamb, cook simply and shredded so that it is easy to digest.
Chicken and rice is a good food for sick dogs and will also help to settle their stomach and also give them some much needed nutrients. Also make sure that the dog is drinking plenty of water. If teh dog continus to not eat then a vet should be consulted.
If he's not eating you should try some chicken and rice, mixed in with his dog food. You could start with human baby food Chicken and Rice also. If that doesn't get his appetite take him to the vet then.