Hi Welcome to health care magic forum,
Ear infection,throat infection
with cough and cold with running nose and high fever indicate upper respiratory infection
But if it is frequent than it could be because of acute or chronic adenotonsilitis.
Adenotonsils are lymphoid system
of the body which guards around aerodigestive tract against common pathogens.
But itself get infected sometimes and become source of infection subsequently.
You can give your grand daughter antihistamine drugs for a month or two. Avoid cold ,head bath and cold foods/drinks.
I would advise you to see an ENT specialist
for thorough examination.