If his tummy is upset you can withold food for about 24 hrs then start him off on a bland diet of chicken and cooked rice. Maybe a half cup to start with as long as he eats it you can give a bit more at the next feeding.The next day if he hasn't thrown up start him back on his reg food. For water see if he will take an ice cube and eat it,if not, do not allow this to go on too long or he will dehydrate,see a Vet. The scooting is usually full anal glands. These may need expressed.Sometimes they return to normal without intervention,sometimes not. Your Vet can show you how to express these glands,be aware,the fluid that comes out is very smelly(even smelly is too mild of a word)they stink like heck.