I'm taking care of my 88 yr old relative. I'm about lost. Any advice?

I started being my Aunt's caregiver about 3 months ago.At the beginning of this caregiving.I talked with my Aunt about what she wants.She tells me she doesn't want to go to a nurcing home.She wants to live in her own home alone till she dies.I told her that I will try my best to avoid her from going to a nurcing home.
I go to her home to check on her every other day to make sure she has what she needs as a caregiver would.My wife and I talked to her about us moving in with her as live in caregivers.The Aunt refuses. She wants to live alone.She's affraid to leave her house ,she feels she needs to guard her home at all times.She's 88 yrs old and forgetting many simple things.My Aunt is 88 yrs old and compatent to do what she desires to do until told by a doctor other wise."She is not incompatent".
She's forgets,everyday I go see her she needs to be reminded.I call it rewinding a tape everyday.Seems the only thing she has no problems doing is paying her bills.She's been my Aunt for over 40 yrs.Many times she forgets my name and calls me by another.At times I just ignore the wrong name she calls me by and go with it.She forgets what day it is,She forgets what she did yesterday.She moves things/items around the house and misplaces them accusing us of taking or moving things.I try to leave her notes to help her remember but,she get's upset saying her memory is just fine.She's denys everything saying there's nothing wrong with her memory.Seems to me she lies to her doctor and many others as fooling them so she's not told incompatent.She's a very sneeky lady.Not only sneeky.She's a very hateful person.Mood swings every 10 minutes each day.She blaims me when she misplaces things.She never leaves things in one spot.She gets bored and starts moving things around the house then forgets where she placed them.
I feel she is lazy to go to the bathroom.Lazy maybe the wrong word to explain but,that's what I feel.She has large coffee cans near her bed,where she seats around the house and urein's in them.Why she don't have a bed pan is beyond me.You would think her visiting nurce would see this stuff she's doing.But,it's like if her visiting nurce is blind.She has problems bathing on her own.She takes bird baths so to speak.Her bedroom and where she seats smells like urein.We change her sheets on her bed on every visit.And wash her cloth for her.
I do the same as any caregiver would do and then some if not more.The wife and I don't get paid for any of our services we do for the Aunt.Seems it isn't fare or right for us to have to take from our own pockets to do this job.From our time,gas money and ect.This isn't our Mother or father were taking care of.This is a Aunt.The Aunt choice in her life to not have children of her own.This is the result of that idea of not having children.There is no other family or friend willing to help her.She was abused by her past caregiver.The past caregiver went to jail for battery towards the aunt.Every family or friend of my Aunt is affraid to help her.Affraid to go to jail if they try to help her.If my wife and I decide to stop helping her she has knowone to help her.Theres no excuse for the past caregiver abusing my Aunt.That's wrong in every way.The past caregiver lived with the aunt 24/7 and was a heavy drinker.No excuse for abusing her.But,may sound harsh to say but,my Aunt is a very hateful person.And says hateful things.My Aunt treats me like crap basically.Everything I do for her she don't give me credit.She only thinks of her self and only her.She caresless about the time I take out to help her.Most throw blaim on the dementia.Sometimes I wonder if that's just a show to get what she wants.She uses her WILL to obtain help.If you help me I'll put you in my Will.As all elderly people do to obtain help or other.
Anyway,
The past two days when I've called her to check on her she tells me she fell down..Two days in a row?Is it her dementia as forgetting what happened yesterday?Or did she really fall twice?Who knows.Twice in the same spot she said 2 days in a row?I write down on paper evertime she falls so it's noted.She don't want us moving in.She don't want to leave her house to stay with us.I can't force her to do a thing.She's compatent.It's like a rock in a hard place for me.She don't want anyone living with her nor willing to go live with someone else.She feels she needs to gaurd her home at all times.I am her DPOA.But,yet she's compatent.I feel my Aunt is incompatent to do things on her own.I feel her doctor isn't a very good doctor because,he doesn't see this.I feel the doctor knows she's incompatent but,avoiding to tell her.Like if the doctor is waiting for me to be the bad guy to make her incompatent as say the word.My Aunt would disown me if she knew I was the one that made her incompatent.What do I do?