My grandma just got diagnosed and I don’t know what to do

I’m 24 and my grandma just got diagnosed with dementia after a fall that had her in the hospital for a month. I moved back to my hometown to take care of the business she built and take care of her. On doctor recommendations, she went back to her house after the hospital and had care and support setup for her. She refused all care and support. I’m worried about her refusing to go to the doctor. She keeps showing up at the shop, but all she’s doing is getting the financials mixed up. She refuses to let me help with them. She’s irritable. I’m trying to be compassionate. If I start feeling myself get upset because she’s lashing out at me I redirect the conversation to something that’ll make her happy. I’m trying to make sure she’s eating, drinking water, and taking her medicine. I’m trying to keep the business from going under. I have emotional support for me, but no one is helping me with explaining things to her or helping her to understand why certain things are being done now. I have no experience with this. No one I know has any experience with anything remotely like this. I’m trying my best to do what right for her, the business, and myself. I just go home and want to cry every day. I’m so overwhelmed. I just needed to vent.

Thank you,

A scared 24 year old