My 88 year old Mom lives independently in her home. I visit daily and help with any needs she has. My concern is she is sleeping so much.

MIL sleeps a lot during the day (and intermittently at night *sigh*) As long as all other health seems good, it's probably normal for her age.

I was just visiting my 88 yo uncle and aunt, we were talking, all of a sudden he left the stage...sound asleep! My 94 yo mother also sleeps a lot. I attribute it to age, their health is ok for their age.

Does she have signs of any other health issues going on? Is she eating? Alert when she’s awake? Mobile? Then I wouldn’t worry about it. Us elders are known for dozing off, sometimes at inopportune moments. She may just be bored. God knows there’s nothing on television and she may not be interested in reading. She’s lived along life and she may figure it’s her time to do as she pleases. What would she be doing if she weren’t sleeping? Does she attend a Senior Center? Talk to friends on the phone? If you are worried, speak with her doctor.