VET ASAP.
When puppies do not eat or drink it should always be treated as life threatening.
Bloat can be life threatening. This might be a twisted stomach,some breeds are more prone this. Was your Dad feeding him and ,if so what?
Only first aid I know about, if it is gas,is a stomach tube but even I would hesitate trying that.
Agree, would try to get the pup to the Vet ASAP!!!!
How old is the dog, what breed, and what are the other symptoms besides the bloating and decreased appetite? Any vomiting/diarrhea/trouble breathing? I would suggest gettting the dog to a vet right away; time could be of the essence if he is experiencing GDV (bloat)!