S.M.
Hi G.,
My Name is S.,
I am not a Doctor, so I can not give any medical advice. I have worked at a Pediatrics Office for 7 years and my son had such awful ear infections as well when he was an infant.
Try Pedialyte Popcicles, that usually keeps them hydrated without vomiting and this worked for my son. Even the generic brand if more affordable. I would hold off on the juice until the diahrea and vomiting stop. Water and Pedialyte are better. Instead of juice; you can try the Pedialyte drink- my son would only take the grape flavor and you can give it with water. In a bottle -- half drinking water and half Pedialyte.
I have 2 children ages 11 and 15, so I have been down this road a few times and I am glad to help as much as I can.
I hope this helps.
Sincerely, S. :-)