Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today.
I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your situation, and wanted to help.
Now if he eats cooked meats and an imbalanced diet that will upset his good gut bacteria letting other ones (gas producing usually) flourish. So, these signs may be from the diet, though we cannot exclude a gut infection (eg viral, bacterial, protozoal, worms) or dietary indiscretion with Stitch. So with that in mind, we can try some home supportive care just now. To do so, let's put him on an easily digestible diet like cooked white rice with boiled chicken, boiled white fish, cottage cheese, scrambled eggs, or meat baby food (as long as its garlic/onion free). The aim of these diets is that they will be better tolerated/absorbed by the compromised gut. Therefore, it should get more nutrients in and result in less GI upset/diarrhea. Fiber (ie canned pumpkin) and OTC probiotics (ie Benebac, Fortiflora) can be added to these meals to firm those loose stools quicker and support digestion. And I would absolutely use probiotics for Stitch given the gut imbalance he likely has. Activated charcoal used for treating gas in people could be used as well.
As well, since he sounds to be very loose, you can try a pet safe anti-diarrheal too. As I am sure you appreciate, these would not be a cure for infectious issues; but it can still be of benefit. It will reduce diarrhea load, allow the body to absorb more water/nutrients, and soothe the upset gut. In regards ***** ***** options, the one we most commonly use is Kaolin/Kaopectate (More Info/Dose @ http://www.petplace.com/article/drug-library/library/over-the-counter/kaolin-and-pectin-kapectolin-k-p)). This is available OTC at most pharmacies. Otherwise, Propectalin, Canikur, Fast Balance, and Protexin Pro-Fiber (all OTC at vets, pet stores, and even Amazon) would be another option. All will slow diarrhea and those last ones have the added bonus of providing support to the delicate good GI bacteria. So, these can be used as a short-term means of soothing his upset GI.
Overall, these signs do raise some concerns here. Therefore, we’d want to start supportive care to settle Stitch's gut. If he doesn’t respond to the above within 24 hours; then we'd want to get a local vet involved. They can assess his hydration, test a stool sample, make sure there is nothing in his stomach that shouldn't be there or any sinister viruses present. Depending on their findings, his vet can treat him with antibiotics +/- anti-protozoals as needed to nip this in the bud.