If your pup still has
major diarrhea, one suggestion would be to rest his gut from food for 12 hours with offering water only.
If you feel he is ready for food, mix equal parts of boiled, shredded, boneless chicken breast with plain canned pumpkin (no spices). Feed a small meal and watch. In a few hours if no diarrhea, feed another small meal. If he handles this, switch to a full size meal and keep him on this mix for one or two days to let his gut rest. If all is well, begin to introduce his regular food in small amounts and wean off of the chicken/pumpkin mix.
Slippery Elm capsules opened up and mixed with his food can sooth the intestinal tract. You can purchase this at a local health food store. Good to have on hand for tummy upsets and diarrhea......dogs or humans!