I wonder about this too. My wife has Alzheimer's along with "paranoid ideation" and the Quetiapine (Seroquel), taken am and pm, helps the paranoia and hostility, but she sleeps 10 hours at night and takes a two hour nap in the daytime. Sometimes she takes two naps. But I haven't looked into this with the Dr since she panics if I am not with her every moment of every day, and her sleeping gives me an opportunity for some alone time. This has been going on for about 8 years now. I often wake her up if the nap goes on more than two hours. I don't think I am a terrible caregiver, but sometimes by the end of the day I am spent. Caregiver burnout, they call it, or a new term I ran across, "compassion fatigue. I empathize with you and what you are going through.
I also think that the after effects from anaesthesia can cause all sorts of lingering issues, as I have experienced some personally, including loss of taste and smell for many months.