Today My Boyfriend Had A Scary Spell. He All Of

Today my boyfriend had a scary spell. He all of a sudden started dripping with sweat and then just fell over. Completely blacked out, was mumbling strange sounds, his eyes were open but he was not responding. He was like this for probably under a minute. He finally came to and said he didn't remember much. He said he heard a "pop" noise and the next thing he remembers he was on the ground.