Hugs (from a distance
) to all the families with sick little ones (and selves, too!).
I'd never heard that water is "harsh"-- just that it's devoid of most nutrients and minerals when any spare nutrition can be vital.
I've actually never used those expensive, IMO unnecessary electrolyte solutions. Watered down apple juice, flat 7-up/Sprite, and chicken broth (preferably homemade, with lots of garlic & onion, which are excellent for stimulating the immune system & fighting bacteria) do the trick nicely. They may not actually cure the cold/flu, but they DO help enormously to keep dehydration at bay, while offering the benefit of sugars, salts, other minerals, and in the case of broth, protein. Ginger is calming to the stomach, hence the old recommendations to drink ginger ale. It has to be flavored with *real* ginger, though. Same goes with ginger snaps. They can be tasty and helpful if they actually contain ginger, not artificial flavors and such.
Tylenol and other OTC medicines are *very* hard on the stomach. I wonder if Tylenol would help, or rather worsen stomach cramps, honestly. An upset stomach can be soothed with chamomile or peppermint tea (more of those vital fluid, as well), sweetened with honey; a sure kid-pleaser. Chamomile can help with discomfort, restlessness, sleeplessness, crankiness (generally calming and soothing) as well. Pain relievers/fever reducers are best left for those times when the child is in obvious distress from body aches, headache, general malaise, and when the fever consistently remains above 102F for several hours.
Fever is not the evil affliction many of us have been brought up to believe it is; it serves a very valid and vital function of raising the body's temperature so that whatever virus/bacteria is present, cannot easily continue to reproduce itself and further infect the body in an environment too hot for its needs (if not killing it off altogether). If the child is not in pain, I avoid using fever-reducers until around 103F. It depends from child to child and situation to situation, but I have a much higher "comfort level" than other folks I know IRL, letting the children sleep it off under the fever's influence, rather than medicating them, having them instantly zap back into their normal selves, boisterous and chipper, only to end up even sicker (and usually a visit to the ER) after the meds wear off.
Obviously if the child is having pain or discomfort, all bets are off and they get the medicine they need to be out of pain if possible. If your child has a history of febrile seizures, by all means please follow the instructions of medical professionals rather than what I or anyone else intends as helpful for common, everyday situations.
If your child isn't hungry while they're suffering from stomach upset, it isn't important to push solid foods, and may only worsen the situation. Traditionally the BRAT diet was recommended (bananas, rice, applesauce, toast), but it's fairly safe to offer whatever bland foods the child is used to eating. If they hate applesauce but love diced pears, go for it. Toast=crackers=plain pasta=dry cereal=plain oatmeal/cream of wheat/whatever other bland grain-based starch you can think of. Dairy products aren't usually recommended, because cow's milk proteins can be difficult to digest when the stomach is upset, causing further discomfort. This does NOT apply to breastmilk. Breastfed babies with a virus are a whole 'nother post!
Just think bland. That's *if* your child is hungry in the first place; chances are, they won't be.
I hope everyone is feeling well again soon! Poor little guys & gals....