Could his drink of been spiked?

My friend had a fit last night, for the first time in his life i think it's so unusual, he had it in the toilets of a pub and went to hospital. He's not epileptic and we think his drink was spiked. He was throwing up a watery like fluid, in the hospital he threw up a yello/green fluid which the doctor said was bile. He didn't remember much, what could of happened? Spiked drink? He only had 1 coke, half a can. Could it be related to him staying up and lack of sleep. He has been lacking sleep for a few days now.