Rapid cognitive decline like falling off a cliff after a chronic stroke. Anybody else have this problem??

Brain damage from a stroke is progressive. The brain doesn't regenerate, the damage continues like chain reaction is an unpredictable way.

My 91 yo mom had a left brain hemorrhagic stroke 5 weeks ago. Main symptom was severe headache. She became more confused over the next 24 hours, and was diagnosed at urgent care with UTI. Finally an MRI showed a bleed. She has also lost ability to do simple tasks and cannot remember one minute to the next. She improved after 16 days in hospital, but has not improved cognition at all after being home 3 weeks. Her speech has become much more coherent though. I was told improvement can be over about 3 months.

Yes have seen this.
Swelling? Extention to a brain bleed? More micro strokes?

I never found out the reason, but have seen a big drop in skills 2-3 weeks post stroke.

Yes strokes are not always seen on imaging. MRI better than CT but small strokes can still be hard to dx (until later, if at all).

Yes it can take time - to see what can be recovered & what becomes 'the new normal'.

That can be a scary place. Thank goodness he is not always alone. As the girlfriends know him well, they can call Dr or EMS for any new or worsening symtoms. Email/text them the F.A.S.T stroke guide if they are not familiar with it.

PT can be arranged for home rehab & regular Dr checkups to keep a closer eye until things seem to stabilise.

The highest risk time for a stroke is within 2 weeks of a stroke. Small strokes can be warnings of a larger one.

If he does not have a medical POA, right now would be the time to do so.

On the "refusing to admit anything was wrong" topic: stroke is a brain injury. If you break your leg, you can see it & feel it. But if a little brain 'breaks', the brain may not know it, not 'see' or feel it. Look up *anosognosia*. It is a real thing & very very common post stroke. People have told me they just lay on bed, or on the floor, calm, no pain but without a thought in their head. No concept of "I fell" or "I need to call for help". Just calm. Sometimes people try to call out but have lost speech.

That's why more eyes are good. They can raise the alarm if he can't. It then extents to not realising home help is needed. That finances are now muddled, driving, cooking may be unsafe etc.

I am sorry for the hardship of this situation, especially being far away. The only good things I can say about stroke is most people report no pain (some maybe a sharp headache) but often, no pain at all. My relatives that went that way didn't seem to suffer.

And that many people do make recoveries. Not always full like as before, but to enjoy a good quality of life.

"What really matters" is an excellent book & really does help to navigate what is important when turning down Old Age Road.

(((Hugs)))

It is shocking the first time you see someone try to turn the channel with the phone or has forgotten how to use the microwave. Neighbor with Parkinson’s wanted help from my DH to turn the heat on. He asked where was her thermostat and she handed him the remote.
I’ve seen four people have these issues and the only thing they had in common re diagnosis was that they were all elderly and lived on their own.
I understand how frightened you are for your dad. And the other thing is the next time you see him he may not be confused at all in that moment with those devices and wonder what the heck you are going on about. (Rereading your post and see that has already happened).
FIL once wanted to help the guys out when they had the hood of his car up (pretending to repair it after they had disabled it). He came out with a wine opener thinking it might help. He had suffered a head trauma 10 years earlier.
Things wear out. Old injuries show up as arthritis, etc.
I am sorry your dad is having issues. It takes a minute to absorb and decide on next steps. Deep breaths.
You might like to pick up a copy of “Being Mortal, Medicine and What Matters in the End” by Atul Gawande. There are some great questions to ask dad included and also time to make sure you have the proper paperwork in place to help manage his care. POA, Will etc.

Your father does have vascular dementia, not Alzheimer's. Vascular demencia is caused by injury to the brain cells from oxygen deprivation when large or small vessels get clogged with blood clots or arteriosclerotic plaques. The MRI only showed a large infarct in the left ventricle. However, MRI's can not detect very small lesions caused my mini-strokes. It's most likely that your father's worsening dementia is caused by additional mini-strokes that he continues to have. His condition is likely to progress in a non-predictable manner. There's no cure for vascular dementia and the worsening can be rapid.

This happened (sort of) with my brother. He lived at one end of California and I at the other. He was fine, when suddenly a call asking if I knew he was in hospital after a serious accident with truck; head trauma on two sides. Then the "incintal finding" of a tumor, old, calified, but an explanation from hearing deficit in left ear, but THEN a diagnosis of probably early Lewy's Dementia due to his symptoms, not findings, and his balance, which could be from this or from that.
What was missed I found at home. Reports of people that balance was seriously off in last few days, and then l description hand written in his beautiful writing done on Feb. 11th followed by one in which he could barely write at all. My dx. would be probable stroke. But hey, could have been all three. As my MD once said "it's anything but an exact science".
Strokes are difficult to pinpoint often enough in scanning. Brain bleeds, or hemorrhagic strokes show; others often don't and again you are left with symptoms.
So as you said, this is sounding like stroke. Your best bet is a sit down with a neuro psyc, and the details you give us here. Though at this point it is rehab and looking 1 month forward to know that any swelling is down and what you are left with is what rehab is left with to work with.
I surely do wish you good luck.