Check the temperature once Normal temperature of cats is between 100-102
If the temperature is not in that range then it can because of any underlying infections
And the vomiting and motions can also be because of that
Give him electrolyte and ORS mixed water to drink
And also give him sucralfate syrup that will reduce the vomiting s
Then try giving the ors and electrolyte powder
And also give sucralfate syrup that will reduce the vomiting
To reduce the motion u can use prebiotic powder like gutwell mix it with food and give