m1ssjess89, a power of attorney gives someone the ability to take care of financial affairs (dealing with bank accounts, real estate, entering into contracts, etc), the agreement that relates to medical care, and where someone lives is called "Guardianship", and a particular type called "Enduring Guardianship" will continue to have effect once the person no longer has the capacity to make decisions for themselves. You should check whether your mother has enduring guardianship over your grandfather.
I am not a lawyer, but my understanding is as follows... The person granting the guardianship (your grandfather) may withdraw it at any time, as long as he still has the mental capacity to make decisions for himself. If he no longer has that capacity, then it is assumed that he entered into the guardianship when he did have the capacity, and that now the guardian is acting in his best interests (and any disagreement by him is a result of his lack of mental capacity). I believe that NCAT is the place to go to get a determination of their mental capacity, or to challenge a guardian's actions. More details can be found here
Enduring guardianship - Guardianship Division and
Appointing an enduring guardian - Legal Aid NSW
HOWEVER... Please consider the following. I am not saying that you shouldn't act to protect your grandfather's interest, but please make sure that you are doing the right thing, both for your grandfather, and for your mother (who is probably quite stressed and upset about the situation).
I have seen some of this in action (the guardian putting a parent into a nursing home against their will) and I would strongly recommend that you look into the reasons behind your mother's actions. People with dementia usually do not realise that they have it (a Doctor once said to my mum "If you think that you've got dementia, then you haven't") and your grandfather not wanting to go into a home is not unusual, even when the patient really needs that level of care. Also, dementia patients will have good and bad days, and have good and bad times of the days (evenings are often bad times) so if you've only been visiting occasionally, or just during the mornings then you may not have seen him at his worst. Additionally, did you see him much when he was living without assistance, or just when he was in nursing home care? I know from experience that the symptoms of dementia will reduce when someone is in appropriate care. You should also talk to your mum about why she is no longer willing to care for him at home. From your post, she seems to have been willing to go out of her way to help (building a granny flat isn't a trivial exercise, nor is it cheap) and I would imagine that she has given this serious thought before changing plans. And finally, have you talked to the staff at the nursing home? They are professionals who have been caring for him on a daily basis during his respite, and will have a reasonable idea of his condition (and I would imagine that they'd be the first people that your mother would use as witnesses if you contested his mental capacity). There are also dementia support services around that the nursing home would be able to provide information on.
My mother in law was put into a nursing home about 12 months ago with dementia. The dementia was never officially diagnosed by a doctor, but she was living by herself and gradually declining (she was living in the country, about 8 hours drive from the nearest relative - my wife - so didn't get much family assistance either). My wife noticed that she was having good and bad periods when talking to her on the phone, and started making more trips to visit on weekends. Every time she got there she noticed mouldy food in the fridge (meals on wheels was delivering the food, but she was forgetting to eat it) and various odd tablets left around the house (medication that she forgot to take). My wife would clean and ensure that she ate (she was only there for about 24 hours each visit) which improved her mental state at the time, but each time my wife went she was a bit worse. During this time, my wife arranged an enduring power of attorney and enduring guardianship. Eventually my mother in law found that she was unable to get up and called the ambulance, at the hospital she was found to be severely underweight and unable to recognise friends (including her neighbour of around 10 years). We arranged a nursing home near where we live and brought her back with us and she improved immensely in a very short period. The nursing home ensures she eats enough (and adds supplements to her food), they ensure that she exercises, and they keep her in a nice regular routine. This has made a massive difference to her mental state and her quality of life, but also means that she thinks that she is capable of going back home. She usually appears quite normal when we visit, and my kids haven't really noticed anything, but occasionally something different will happen (like a Doctor's appointment) and she will just be unable to handle it, and my wife and I also notice her issues when trying to arrange anything with her (like getting her to remember we will be visiting again in a couple of days). Once one of the nurses even said that sometimes when talking to her you wonder why she is in the nursing home, but other times you know exactly why she is there. She seems to like the place (she keeps saying how wonderful the food and the staff are) but will regularly demand to know when she is going home. The whole ordeal really upsets my wife, partly because she sees her mother declining when she is used to being supported by her mum, and partly because she is forced to make decisions on her mum's health against her mums will (she really didn't want that responsibility, but can't in good conscience palm it off onto anyone else). Luckily her family is supportive of everything that she is doing, if she had a relative taking her to court then things would be unimaginably worse for her.
It is great that you are taking an interest in your grandfather's well being, but please check that you are doing the right thing before adding additional stress in these already very difficult times.
