Hi Lexie, I have an idea of what you're talking about here. My mother, a widow for 10 years was coping less and less in her house. Thank goodness, like yours, she decided to move into assisted care and I went over, moved her in, packed up the house, ran a garage sale. My sister has financial POA thank goodness so she handled the money side of things. My Mum is my hero because she decided to move into assisted accomodation, even though she didn't want to, because I told her what a strain supporting her was putting on my sisters who lived nearby.
The thing is they cover up declining mental capacities so well that even their health providers fail to catch the early stages. Also they're often unaware that they are coping. My mother always kept a clean house, but on my final visit I found dirt behind everything, out of date food, mouldy fruit in the bowl.....This is why I'll always be grateful she moved of her own accord.
She is doing much better now, has gone from emaciated to a healthy weight and is being well monitored by the staff. She also goes to the gym still and physically is in outstanding form for her age.
Hint: buy your D & SM a clock which gives them time, day of the week and date, and a calendar with plenty of room to write dates on. A small wipe clean board is also useful for reminders.