Hi there and Welcome to YT ! I am sorry your got your puppy from that breeder... but, now it is your job to keep him healthy .Do not feed your baby meow Mix, that is for cat's. feeding ham is way too salty and fatty . Did the vet suggest anything ?
I would think canned puppy food if he will eat that. Or Chicken and rice, using the white meat only. You could mix tiny bits of vegies .OR mix the chicken with the canned puppy food. Buy a high quality canned puppy food too.
Make sure he is drinking water too.