How to feed him when he won't eat?

Continue with free access to water. Keep him warm & comfortable. Continue with the rice, but I would avoid the egg. You could also try feeding cooked pumpkin. You can find it in the grocery store, just make sure you don't use pumkin pie filling-just plain old cooked pumpkin(ingredient list should read pumpkin,water,salt & maybe squash-nothing else). Feed small amounts of rice &/or pumpkin. Try a tablespoon or 2 hourly.If he shows interest in trying more add another tablespoon. Until he is eating he will lack bowel movements & be lethargic. When/if he does have a bowel movement, pay close attention to the colour & consistancy. If feeding pumpkin, it will be orange,just to forwarn you. Also pay attention to the colour of his urine. Note any difficultly passing either. I noticed that you stated you phoned several vets. I am surprised that none of the vets you called suggested you bring the dog in,just to be sure.Do you not have a specific vet who you normally see? If so, make an appointment first thing Monday morning(if they aren't open weekends). If not find a vet & request an appointment.

The one thing you haven't tried is actually taking him to the vet. They can evaluate him in a way you cannot describe over the phone to them. Please don't wait. Not eating...excessive water intake ... this is not something that passes.

And to answer your question, try chicken broth and continue with rice with small amounts of boiled chicken. Best of luck.

Add: "weak bowl movements, lethargy, and he is very weak"

The only thing I can add is that by the time you take him to the vet, it may be too late, or a simple fix may now be an extensive, expensive one. Many things pass, true. But when a dog becomes lethargic, weak, and stops eating, what more information do you need before you humanely provide medical treatment??

Add 2: And as for 'flu' - that's a crock of shite. I had a dog who had flu like symptoms - mild diarrhea, some lethargy, but she ate and drank fine. Turned out she had Acute Lymphocytic Leukemia, and she was dead in a week.

Just wait like the vet said. If it gets worse then i'd worry. I'm sure he will be fine. I always think the worse when mine are ill and they've always been fine. Just give him lots of cuddles :)

How long has he been sick? If it has been more then 24 hours, it is more then a stomach flu which is rare in dogs anyways. If this has been going on for less then 24 hours, just fast him. This will give him a chance to heal. By fasting, I mean that that he is not offered any food. He can drink all the water that he wants as long as he is not gulping it down and vomiting it back up. Do this for 24 hours. Start adding small meals after the fast. If this doesn't work he will need to see a vet right away. Sounds like he may need to see a vet sooner more so then later.

just give him time he will eat it when he is comfortable and some times just walk away he might feel pressured if you are watching him

Any vet who tells you your dog has the 'flu' is an idiot.

It could be any number of things, from an ear infection, to an abcessed tooth, to cancer.

Find out what the problem is, babying him will not make him better if he really is sick. And if he isn't sick and just spoiled and waiting for you to offer him something better, you are making the problem worse.

Can I just clarify something please? You are trying to feed your dog Cucumber and radish Salad? Why? He is a dog. If he were wild he would be catching rabbits and other animals to feed himself, he wouldn't be eating grass and vegetation all of the time. Yes some dogs like to eat some vegetables. But you can't punish him for doing what is natural to him. You have personally chosen to become a vegan. But the dog has no choice. Please feed him meat and normal dog food, it is cruel to feed him such a poor diet. if he has a weight problem, buy him an obesity food from your local vet or pet store if they have it and feed him the lower recommended daily amount. if you have concerns about his health and well being contact his vet and ask to have a consultation with them regarding food and your views.

I don't scoop by Dobermanns up & dash to the vet for the smallest of reasons, but a dog refusing food is a red flag to carefully note symptoms for any sign of deterioration or lack of improvement for no more than three days.

After that I want a hands on examination by a vet, possibly x-rays to check for an obstructions & whatever tests are deemed necessary to get to the root cause of the dog's reluctance to eat.

If the dog doesn't want to eat you cannot force it to, so in your shoes if the clinical symptoms were the same on Monday, it would definitely be taken to the vet.

Just bring your dog into the vet. If he's lethargic, has diarrhea and won't eat he needs to see a vet. One of your earlier questions said the dog is always getting into the trash can--maybe he's eaten something that has caused a blockage.

Glucose might help. It is better to feed him diluted glucose in a syringe.

Keep a log of what he eats, drinks... so that when you take him to the vet you can give a clear account of his progress.

I gather his taste buds don't really work well so that he doesn't want to eat. If he drinks so much water you might want to make some congee for him (boil a table spoon of steamed rice with a cup of water for some 20 minutes). Add minced meat to the congee to make it tasty. You might also want to give him baby food.

Steamed rice boiled in water could be a good fluid intake for him too. It is soothing for his stomach.