Caring For Aging Parents Support Group
Caring for aging parents can be a difficul time as we become the caretakers for our parents. This broad responsibility can encompass such services as assisted living, adult day care, long term care, nursing homes, hospice care, and in-home care. Whether you have just started caring for your parents or just need a place to talk, we're here.

That ex-sister in law of yours sounds like trouble. What does your brother who was married to her think about her being involved?
You and your siblings may have to take action, talk to a lawyer about your options. Even if you don't use legal options, knowing what you can do is very helpful!
How has your dad dealt with basic (logical) questions about his plan to live at his home? Odds are that he is making this decision based on emotion, so you might have to ask some very hard questions about things like him falling and not being able to get up, or even get to a phone to call for help.
A friend of mine installed internet connected cameras inside his mother's house. With her knowledge and approval. They do not invade her private areas (bedroom and bathroom) but cover much of the rest of the house. She puts her purse in a very specific place as a message that she is home and OK.
Sorry to ramble, just getting ideas out there.
Exploring legal advice, but afraid there isn't much we can do.
I think I will bring him home with me for a night and see how he does in my house, see what he can and can't do and go from there
. I foresee lots of research and paperwork in my near future.
The fortunate part is that you and your siblings actually have more pull than a non family member (she is only family by marriage....kids have first rights when the spouse dies). However, checking with a lawyer....probably one that works for geriatrics I think would be your first pick (first consult is usually free, so check around).
My mom is in a wheelchair and in poor health. She and my dad lived 800 miles away from me. The last two years of my dads life, my mom had to have him placed in what was called "foster care" becuz they went through their life savings trying to figure out his mysterious illness and keep him at home for the 21 years which is why my mom lost her own health. It was a really bad situation. However, they got robbed a few times and taken advantage of by many people...and mom kept falling out of her wheelchair or when she would try to get in bed or go to the bathroom. After my dad passed, I put my foot down and made my mom come and live closer to me (I am an only child). She came screaming and kicking becuz she lives in denial and believes she is capable of living alone 3 miles from a main road and 5 miles to the closest town (they lived on a lake lot), so I had to take matters into my own hands (luckily I am POA of their health and estate and I exercised my rights for her own protection and well being). I took her car away as she had had two minor accidents and almost had a major one the day of my dads funeral (started pulling into another lane without looking where there was a fully loaded 18 wheeler). She had a life alert, but rarely wore it claiming it was a waste of money and she didn't need it!
It is like having a 5 year old legally living on their own (no or very little common sense).
Since my mom and I kinda clash as we are both stubborn as mules, I found a Independent Living facility about 12 miles away from me. I found it through aplaceformom.com which is a free service and extremely helpful (it can be used for your dad....don't let the name fool you). We didn't think mom could afford it, but with the sale of her house and a small pension and SS, she will be able to live pretty comfortably for at least 4 more years. I love it as she has a one bedroom, one bathroom apartment. She is entitled to two meals a day in a pleasant dining room....125 channels of Cable TV.....cleaning services....free laundry....garbage service......entertainment/games and outings with bus service included....a pool....access to the internet.....a library......and endless friends (great for socializing which combats loneliness) and fantastic staff that check on her daily.
She has been getting balance classes and a memory class once a week (medicare pays for her to have these services).
Anyways....I hope this helps you get some ideas to help you with your dad. Sometimes ya just gotta help them whether they like it or not. I let my mom stay as independent as possible (I let her do her own laundry and occasionally I bring her to my house for bbq's and she helps cook (she loves to cook).
We go out to movies and meals at least once a week....we have even gone gambling.....to a bookstore....shopping.......and to get manicure/pedicures. This helps keep her connected to the outside world. I know this is not a possibility for everyone, but you won't know until you check into it or have your dad live between you and your siblings or just you if possible. It will take everyone time to adjust. It took my mom this past 2.5 years to adjust....it's been a long exhausting haul, but worth the peace of mind.
I wish you the best with your dad.
Your ex SIL sounds like a real gem. Get POA over your dad and do talk to a lawyer. It is good to know your rights and how to combat your ex SIL.
You can effectively shut down whatever plans your SIL is attempting to put into place by seeking legal counsel and getting the proper paperwork documented.
I would also talk with his doctor(s) and see if they can help in swaying his decision to live on his own considering the circumstances of where his home is located. It doesn't sound from what you've stated that it would even be a consideration that he live on his own. If all else fails then you could look for a home or condo in your area, sell his old house and get him within your arms reach of advice and monitoring.