Try popsicles. Don't give too much Pedialyte it can actually make it worse from what I remember. I kept giving water every chance I could as well.

It's actually my baby cousin she was diagnosed with the flu but Pedialyte isn't helping just makes it worse

If you have started introducing juice that may be the cause. I recently went through this with my little one. I was told to stop juices completely and give her only startchy baby food. Oatmeal, potatoes, rice, bananas. Basically things you can eat with the flu.

Give them a lil Pedialyte and feed them a little more often. Sorry it's not exactly what you're looking for but it's important to keep them hydrated ? sometimes diarrhea is a sign of teething.