Try not to panic!
Firstly, I would get him into a routine with his meals and stick to it. Don't feed him on demand, and make sure you are not over-feeding the wet food. So many kittens end up with diarrhea purely because they are over-fed.
The anti-biotics should clear his tummy problems by the time he has finished the course. Try feeding him plain chicken for 3 days (no rice) and then gradually introduce his normal diet. Little and often is better than large meals twice a day for now. I always recommend a holistic cat food for poorly tummies such as Eaglepack or Orijen; they are great at settling tummies. I wouldn't go down the raw food route until his stools are normal, and then there is very good info on this diet here:
http://www.bengalcatforums.com/forums/v ... php?t=2008
There is also 'Prairie raw instinct' which is a freeze dried raw food.
Bengals are prone to watery eyes unfortunately. You could try dabbing them with cotton wool soaked in a weak tea solution which is a natural antiseptic.
Most importantly though, make sure he has plenty of water even if you have to syringe some down him! Also, try him on pro-kolin which is a probiotic paste and is usually excellent for kittens/cats with diarrhea.
Good luck and let us know how he gets on!