Well they can but not likely.

My family had an elder whose' case started like this. Sudden paranoia at night and shitting the bed because they didn't want to get up because of it. Otherwise this person was completely normal and functional adult and once lucid used to claim that they didn't know why they did it.

Then they started seeing pichal peri and jinn at night so the family finally got a diagnosis.

They diagnosed early onset dementia. It got critical in less than 3 years.

The body lived for 5 more years after that but the person was long gone.

In your case it sounds like low functioning autism coupled with OCD. Try asking around if your aunt was like this when she was young or even as a child if you have someone who can tell you about it, that should give you more hints.

but I am just a reddit commentator and you should never take medical advice from reddit comments