My 88 year grandmother wants to stay by herself but health is failing. What should I do with this situation?

Hello, everyone. I decided to ask my first question after months of looking at the forums.

My granny is living by herself in a 2 bedroom apt that she has been living in for about 9 years. She is very active in her church as she has been for about 40 odd years. She still works and just stopped driving 2 years ago. I have tried to get her closer to me for about 10 years. 5 years ago we actually went through the process of getting her a assisted living apt complex deposit and all. She came up with every excuse including the leasing agent not wanting her to have the apt. I was working 10 hours a day commuting about 45 mins per day for her to not want the apt because "she wants to be independent for as long as she can" so it was and is a very frustrating situation.

I have a bf of 3 years we will hopefully be getting married within the next year he is very understanding and goes with me to her appts. I have medical power of attorney and am able to take her to certain Dr's Appts when it is planned far enough in advance.She was in the hospital overnight for blood clots in her legs about a month ago and was out for the count for about a week due to the medication causing dizziness. Once she was better she back running around everyday with the church but talking about how tired she is the Dr told her is she had waited the blood clot would have burst and went to her lungs and caused death. Her congregation member took her to the ER instead of the minor medical clinic that she loves to go to due to getting in and out because "she has things to do". The whole time we were there she was complaining about being there alone and that I didn't bring her anything to eat. Hopped up to go to the bathroom even though she was a fall risk and went to the bathroom by herself. Basically hardheaded and playing up her age for sympathy

I am 40 about to purchase a house a 3 bedroom 2 bath house and the only thing she keeps saying is I want to be as independent as I can for as long as I can, while complaining about the bus services, me not being able to take her to dr's appts, not being able to get her packages that I send her due to not being there and missing the packages. She actually canceled a package that I sent her for a heating pad that she needed because after not being there to get the package she "wasn't going to run the people down to get the package is that what I am supposed to do?"

I work at home full time as a teacher and the strain on me its very unbearable and I don't know what to do. It's pulling me in every direction and making it very stressful to me. Her new thing now is going days on end with no phone calls letting me know that she is ok then when I do talk with her" it's no big deal your so busy I just waited for you to call me"

I feel like the only way she is going to live with us is when she ends up in the hospital and or breaks a hip or it's something major. I fear for her safety and her being a walking target when she is out and about.

She likes to also tell me 1 week or 2 after she falls that she fell and has brittle bone syndrome. Refuses to reschedule appts and just refuses to give in anyway that can make others lives easier.

My dad her son is 2300 miles away the only thing he says is you can't make her do anything along with her younger brother that loves to stay with her for a month at a time and then leave her a 100 dollar olive garden card for payment whole other story. Every time she has a dr's appt it's always the Dr says "I can still stay by myself"

What should I do with this situation? Sorry for the length, and thanks in advance.