Has he been to the vet? If not, you need to take him in. Puppies, especially toy breed puppies, can get hypoglycemic and/or dehydrated in a hurry.
I'm not sure what you mean when you say "five days preventive care medicine". Do you mean a dewormer like Panacur? Or something else?
Human baby food and corn syrup is not a balanced diet, and in fact can lead to some serious malnutrition issues. A good quality, age appropriate dog food, either kibble of wet, is a much better option. Kibble can be soaked in warm water to soften it if he has trouble crunching it.
While it's usually a good idea to keep a puppy on whatever the breeder was feeding, if they were only feeding human baby food and corn syrup, I would seriously question their knowneldge of puppy raising.