Interesting experience...please read with an open mind

I am the mother of an adult son with epilepsy. His seizures started as an infant and are very sporadic. He can go years without a seizure, even without medication. We thought he was outgrowing them, but lo and behold, at age 26, he just had another full blown, grand mal seizure. Luckily he is okay at this time. While debriefing a few hours later, his long time GF and he told me this story of his last seizure, which happened at home about a year ago. They are both functioning professionals, so please withhold too much judgment here. But they are both very creative and like to explore the supernatural, such as astrology, types of meditation and yoga that open the mind, etc. So one evening they were at home using a psychedelic drug of some kind. And my son had a full blown seizure, which are terrifying. It is what happened next that is interesting to say the least. His GF says he started foaming at the mouth, making very guttural, non-human sounding noises and trying to push her away. This could be normal postictal behavior except his GF was convinced he was momentarily possessed by a supernatural, non-friendly energy or entity. Please do not confuse this with epilepsy being the result of demon possession. I don't believe that for a second. But my question is whether or not anyone has ever had or heard of a similar experience. Thank you for your time.