I am aware of what lack of capacity means in the context of the Mental Capacity Act 2005. It may well be that your aunt, if assessed, would be found to have capacity but she isn’t behaving sensibly or with her own or anybody else's best interests in mind.
I can see that you posted about your aunt five years ago and said:
… aunt won’t consider a care home as she is fiercely independent and not at all sociable. She was assessed by social care but won’t pay for carers. She is not poor just very tight and will only have the heating on 2 hours a day even in this weather.
You wrote that, as a consequence of her refusing to pay for care, you and your cousins were having to look after her on top of all your other family responsibilities and that it was causing conflict.
When did your aunt go into residential care? If it was recently, then it isn’t unusual to face some weeks or months of resistance over what needs to be done. If that is the case then there is little harm in waiting a month of so but if this has been going on for six months or more, I think you must take action.
At 101, it seems unlikely that she will ever be well enough to live in her own home again, especially if she still has the same attitude towards paying for home care.
I think you have to be practical. It is all very well for strangers to say wait but someone is going to have to sort this out sooner or later. None of you are getting any younger and have your own health issues to contend with. You are just delaying the inevitable. As you say, she could go on for a few years yet but if she wasn’t paying to maintain her house then, it seems unlikely she would pay to do it now so it will just deteriorate even further. If it becomes known locally that the house is empty, it could become a target for burglars, vandals and squatters.
A late neighbour’s house has now sat empty for three years. There are several reasons for that but the fact is that it was a well-cared for house while she lived. Three years later, the roof is leaking, the external paint is peeling and the gardens are overgrown. There are professional executors but they do no more than send a man round occasionally to collect mail.
If your aunt’s house is sold, the proceeds will have to be invested until she dies. If the house is sold for a net £200,000 it could earn her £10,000 a year; £300,000 could earn £15,000 a year and so on. She may not need it right now but does she have enough other capital to pay for care indefinitely? With nursing care costing around £1,000 a week, does she have £100,000 in reserve to pay for two years? It might appeal to her tightness if you explain that the sale of her house could earn her some money. If she is out of touch with what has happened to the bank rate since 2022, she may be unaware that, after 14 years of neglible interest rates for investors, there are now decent returns to be had.
Interest rates are stable right now. Some predict rates could go down this year. This would make the housing market more bouyant but at the same time, with the house already in such a poor state, the worse it gets, the more likely it is that potential buyers are going to want to chisel away at the asking the price.
I think there is a case to be made for the sale being in her best interests.