A little background, I'm a 27yo male and have been a full time live in caregiver for my grandmother with Lewy Body Dementia for the last 6 years. The last 2 years have been a significant decline in memory, speech, motor skills, and constant mood swings. For the first year I had the help of my aunt, my grandmother's daughter, but she has since moved out and comes to help on the weekends. My grandmother has 4 children and 7 grandchildren ( I being one of them ) and not a single one reaches out and asks how I'm doing or how she's doing. I have zero friends and no escape. I was working up until the beginning of 2020 so I at least got out of the house for a couple hours a day. I don't know if anyone will see this just wanted to type it out.
Like AlvaDeer said, I'd give your Aunt your 2 week notice IMMEDIATELY and get out of this situation at once. Not for lack of love for your grandmother, but for sheer burnout and the absurdity of being left in such a situation in the first place. 6 years is 5 years and 11 months too long that you've had this job with no pay and no benefits, so it's time you strike out on your own and find a job that you're paid to do. It's your turn now to develop a social life, find friends and start dating!
Wishing you the best of luck moving out and on with your own life now. You deserve to.
My Husband was pretty much non-verbal the last 5 years or so of his life. he made noises but never spoke. (He did say "ouch" once when he hurt his hand)
Can you get involved with some things that you can do from home?
Tutoring
There are online support groups.
The senior center near me has a program where they have people call Seniors to check in on them, make sure they are ok and just have a chat to keep them company.
Any of these might keep you busy, have an outlet for yourself.
It is difficult. I do hope you have more help than just weekends.
I guess some of would say it is "good luck" to have a grandma who is content with quiet as opposed to the difficulties that hit many elder with Lewy's (tho it leaves YOU with no real communication at all).
My brother had a probably early Lewy's Dementia diagnosis, and he died before it could get bad of another cause. To be frank, I think he was lucky; it was what he wanted; he knew what he had and feared where it would take him.
Good luck and best wishes out to you.