each of your questions is possible

yes the hospital could have given him sedatives depending on the doctor some will prescribe sedatives some wont he also had a saline I.V in at the very least saline can cause a seizure under the right circumstances (maybe not 2 days later however)

he could have faked it

it isnt difficult to fake a seizure and he could have faked them in the past for attention

there could be a medical reason why he had a seizure

  many medical issues can cause seizures

Each of your questions is possible.

Yes, the hospital could have given him sedatives depending on the doctor; some will prescribe sedatives, some won't. He also had a saline I.V in at the very least saline can cause a seizure under the right circumstances (maybe not 2 days later however).

He could have faked it. It isn't difficult to fake a seizure and he could have faked them in the past for attention.

There could be a medical reason why he had a seizure, many medical issues can cause seizures.