1. He suffers from narcolepsy, which causes him to fall asleep unexpectedly during the day.

他患有突发性睡眠病，会导致他在白天意外地入睡。

2. The symptoms of narcolepsy include excessive daytime sleepiness and sudden loss of muscle control.

突发性睡眠病的症状包括白天过度嗜睡和突然失去肌肉控制。