I am sorry to hear you are worried about your dog. My name is Rebecca. I am a veterinarian and will do my best to help.
I see he is not eating, is he at least drinking anything?
If you check his gums, are they pink in color?
Drooling can be a sign of nausea, a bad tooth, pain or swelling in the mouth, and inability to swallow. If he is not drinking, and is drooling and losing fluid in the drool, he will become dehydrated.
If I could, I would take his rectal temperature (normal is between 101 and 102), check his gums to see if they are pink (if they are pale he may be seriously ill), look in his mouth and throat, feel his lymph nodes, check his teeth. If his mouth looks normal, and if he can drink and swallow, I would try giving some famotidine (Pepcid AC) for nausea. The dose is 10 mg per 20 to 40 pounds of body weight.
Let me know what other questions you have and let me know how he is doing. Rebecca