He was with friends who took him by boat to the hospital. Roberts had the seizure and then he fell (obvious chronology for someone hvg a seizure). MSNBC reported "foaming at the mouth" but hospital wouldn't confirm or deny. That would be more of a convulsion.
It's all in the neurotransmitters. Sounds like Roberts' neurotransmitters went haywire today and he'll probably be on some kind of seizure meds for awhile.