how old is your cat? I am a veterinarian so I just wanted to write in and say that while I can't say for certain without examining your cat of course that there is a significant chance that your cat could get better. Sometimes they have these "vestibular episodes" for reasons we can't explain and they get better with time. You just need to make sure the cat can eat and stays hydrated. Of course it could be an ear infection (which would respond to antibiotics although the cat could need surgery) or a brain tumor as well. Sometimes they also have strokes but can often recover, at least initially.
Good luck with your cat, I hope it goes ok. I think it is ok for young children to know that animals get sick too, it helps them learn coping skills.