I'm sorry you are dealing with this. I worried about the same for my dad if my step mom passed before him, enough to the point I told my then wife we would take him in despite his many severe health issues. If it had come to that (he passed away and I divorced) I wouldn't have been surprised if it had led to divorce.

I have given much thought to myself in this circumstance, and have no wish to be in an impersonal place such as rehab/nursing facilities, even if it costs me time here. I feel for your mom, and wonder if being in such an impersonal place with less freedoms is exacerbating her mental decline. It seems to me that when the heart is no longer in ones doings and surroundings it is such a sad place to be. I wonder if it has been accelerating her disconnect as she relives the times and places that held love for her, so much lines are being blurred as she seeks some sort of comfort.

This same scenario has weighed more heavily on myself as I possibly face being in her place in the coming decades. I hope you can get to see her more often as you plan. I miss my dad terribly and it hurts I have no more time with him, even in the state he was in the last several years. He was many years ago before his health issues the patriarch of the family, his strength, intelligence and loving heart never to be appreciated anew again.