I have a 75 year old mother in law that falls asleep where ever she sits down. she will be awake one minute and sleeping or falling a sleep the next . she gets up early but lately she has been falling a sleep more often.we know she has low blood pressure. she says she gets dizzy spells once in a while and she is forgetting a lot. we know she has a blockage in one side of her heart. its 65%. I want to know if there is anything to this sleeping all the time. or is that normal for a 75 yr old women.