Jello juice is NOT a total replacement for pedialyte.
Here's the issue: Our bodies rely heavily on our electrolytes (sodium, potassium, phosphorus) to be in balance for good health. When our electrolytes get depleted, we can go into shock. You see this in people who get "dehydrated", those who get heat/sun stroke, or who have Addison's syndrome.
Our gastric juices are high in potassium. When there is vomiting or loose stool ocurring, potassium is quickly depleted. That leads to dehydration, blood sugar issues, shock and possible heart failure. That's where pedialyte come in...it has potassium. I don't think Jello does. It only has sugar and then the added sodium that she recommended to put in it. SUGAR and SODIUM play a key role in hydration/electrolyte rebalancing, but potassium will still be needed.
Anyhow, yes he sounds sick. I recommend you request to get him put on an IV drip. It will make a world of difference and it will most likely bring him 'out' of the illness. It's amazing but it really works, it works because the children ARE dehydrated, even if they seem fine. When us adults get the flu like that, and then get extremely weak and sleepy, that is what is happening to us- we are in a form of mini shock from electrolyte imbalance.
All moms should research and understand the warning symptoms of dehydration and also of shock, because the symptoms are very mild and common.
Gail