namaskaram ji
my prayers are with you and your dog , ....
if you can get him to drink this is very important to stop him getting dehydrated , ...and I do not know if it is possible but please try , ...this grate an apple , let it go brown , ...try to feed this to him in little amounts at a time , there is a compound in apple which when it oxidises is very efective at settling very upset stomach and dhiorea . it sounds simple but honestly it realy helps in upset stomachs , it is well worth a try while you wait to get to the vets .
wishing a quick and good recovery