If these two of mine aren't dead yet, there is definitely a chance. To me, Everything deserves a chance. They are taking it. if they were in pain, with no hope...it would be different.
They had corid, and wormed (in their weakened state, no worms appeared, but okay that was ruled out) practically starved and dehydrated to death. Have been given: epsom salts (which may have helped initially) herbal antivirals, nutridrench, colloidial silver, l-carnitine and st. johns wort, raw egg, cat food, baby food, tomatoes, cayenne, fresh ground black pepper, tuna, salmon, shrimp, (ETA microwave egg, kefir, turmeric, 15 grain bread, Brazil nuts) depending on what they would eat.
I even started a little EDTA for Poppy when he got worse...I was nervous and backed it off. An x-ray would tell me if it's appropriate. It's pretty safe med, safer than aspirin in humans...
Its not hard or time consuming to take care of them. I should just take the 3 min(per CAsportpony) to tube them twice a day and be done. I just spend too much time, watching them eat, researching researching researching and making food mixtures and watching their movements trying to solve the riddle.
If letting nature take its course is okay with you, for information sake, people with "no intervention" living wills are allowed to dehydrate to death, the doctors told me it's not a painful way to pass.
Next time I might do things differently, but probably not, because you never know.
ETA also. I read that if it's a thiamine deficiency raw egg white can become a thiaminase (antithiamine). No more raw egg!