My mother has trouble breathing when she's sleeping. she sometimes faints when laughs and randomly gets sleepy.

Mom needs to see doc: There is a neurological disorder called narcolepsy in which people fall asleep inappropriately, and experience sudden loss of mucle tone with emotional arousal such as hearty laughter. That may cause a falling to the ground, but not true fainting (loss of consciousness). Breathing trouble is not part of narcolepsy. Sleep apnea, more common in obese people, may cause excessive daytime somnolence.