The MSDA on the internet suggests that ingestion of camphor can cause seizures.
Among other things, camphor is a respiratory irritant and can cause layangospasms and bronchospasms. A normal person experiencing sudden loss of oxygen can experience a seizure.
It is problematical if there is permanant damage, but my guess is that there is not and your son will develop normally without additional seizures.
Thanks for your comments.
It wasn't mothballs that was ingested, but a solid camphor cube meant to be used as incense in religious ceremonies.
I presume what was ingested is what we commonly call "mothballs".
While decades ago these were manufactured from napthalene, due to issues of flammability modern mothballs utilize the chemical insecticide 1,4 - dichlorobenzene (C6H412).
Indeed, ingestion of this substance could precipitate a seizure. At this point, one can only guess. Since the ingestion is a known fact there is no point in ordering an expensive mass-gas spectrometer test forn the presence of a toxin.
The chances are there will be full recovery and no additional seizures, but keep monitoring the situation.