Benebac is good.
I could be wrong but from what I read the pedialyte has lots of stuff in it. And the home made solution is better at this point cause you can control it this is the one I use
½ teaspoon salt + ½ tablespoon of sugar + 2 cups of water – warm slightly to dissolve sugar and salt. Seems like there is only a particular protocol for using pedialyte.
I am concerned your guy has lost so much weight and is lethargic. Do you have a squirrel friendly vet?
Personally .. If I were you I would not dilute his formula much anymore ... What ever formula he was in using - he was not having diarrhea problems .. Keep him on it but feed just below the five percent. One question I have through all this was .. If your squirrel loses weight.. Do you feed 5% of current weight? I can understand a squirrel that weighs 30 grams should be fed only the 5% but.. What if you have a 100 gram squirrel that loses weight and now weighs only 80 grams! Do you take calories away ? I opted to not do that based on another experience . But I did not increase much.