Both on meds. Have to haul both everywhere because neither can be left alone. The one with dementia also has a bad heart. He is on hospices and the other gets ups and downs. I put my father in respite care for my first surgery and now no one want me to take him there again, because he was not happy. He does not want someone he does not know taking care of him. They told me when I started that I would get paid, well that was six months ago. Now they say he is going in a home, just to find out today from the grape vine, they are no closer then six months ago. I want out. I am not in charge legally and can not make desisions for them, but I feel I have to do a lot of foot work.
You won't get through this without a spine & boundaries.
Don't be the doormat.
You said "You feel..." Well, stop. You don't have to fill in for what others aren't doing. Stop doing that. Not gradually. Not over time. Not tomorrow.
If dad has dementia, he is not making decisions about his care and safety any more. Whomever has the power of attorney document does.
If nobody has the legal assignment of POA, then you need to get social services involved. They may need a court-appointed guardian.