I would withhold food for 12 hours and if no diarrhea or vomiting in that time give him a very small amount of boiled chicken and white rice. If after two hours, no further diarrhea or vomiting you can feed a little more. Keep on bland diet for 48 hours and slowly reintroduce his regular food.
Here is a link to over the counter meds for dogs. Pepcid would probably help his tummy feel better. Pepto is also listed, but for some reason my vet doesn't like it when asked he said you had to overdose to be of any value. Simethicone (gasX for babies) would also help with the farting if his stomach feels tight and it seems like it is bothering him.
OTC Medications