Not sure if it is dementia or side effects from her medicine?

My MIL has been in and out of the hospital this whole year and is now in a nursing home. Over the past year we've seen some signs of forgetfulness or irrational decisions that made us raise an eye-brow, but nothing too concerning. Over the past 3-4 months her mental state has rapidly declined.
She is on oxygen, she was on morphine for pain in January, but they have got her down to oxycodone once a day if needed. She did have a UTI a few weeks ago, but that has cleared up - I know all of these can affect her mental state. She's only 65, but has had a long lifetime of health problems.

She is very confused and becoming combative with nurses. She has no grasp of time and is showing obvious short-term memory loss. My husband will talk to her and she will seem fine and understand about why she is in there and then the next minute she's texting all of the family that the nurses are trying to kill her, withholding her medication (which is not true), she doesn't know why she's there, etc. She will have good days and a complete 180 the next day, saying she's going to call an Uber and take herself home because she can't live like this anymore. We haven't requested any cognitive tests yet, bc she's in a terrible nursing home and we're focused on trying to get her transferred to be closer to us (4 hours away).

I'm not sure what I'm hoping from this rambling post. We're just at our wits end. No matter how hard we try to make things better for her she ends up somehow making things worse for her self.