yesterday we fed him (our meal) of Vegtable soup (in a packet)
This actually made me laugh out loud! you ask why he is ill and you fed him the most random food ever. They actually make dog food for dogs! they research what dogs need and put it in the dog food. I know you said you do give it dog food, but you definitely shouldnt swap to random soup and cookies when its ill, you should continue trying to get it to eat its normal food and take it to the vet.

and as everyone else said, never give dogs chocolate!