The old man doesn't like his narcissistic family member "caregiver" who has him persuaded he needs her. I went away a couple of weeks and came back to find him half-starved. Skin grey. Drawn and weak. Pressure sores from being in one position on hard sofa day after day.
I have little influence but feed him well when he's with me, prolonging his life and mending his body ills, while his dementia and body ills continue unabated. He always will choose this family member's version of the situation over mine. Is it wrong to let him stay in his house more and when he's with me give him the un-nourishing food he prefers? His family member likes it when he's w/ me, so can live life unrestrained in the demented relation's house. I'm pretty much helpless and in despair. Social services in his area unhelpful.
Thus, I feel if an elder needs more care then we can handle, it is time for the experts to step in. I know for my Mom, she needed a village of professionals to help her, because I just couldn't do it.
Is the "old man" your father, or grandfather, or another male relative? Would he be able to budget to live in Assisted Living? If not, maybe he can apply for Medicaid [which is different from Medicare] and move to a nursing home. Depending on his age, if he is in his 90's, folks of this age think nursing homes are asylums, which is how it was back when older relatives need to be placed into a "home". Now a days, Assisted Living/nursing homes are more like hotels.
Remember, dementia will just get worse over time. As for food, if an elder says they want ice cream for breakfast, ask if they want one scoop or two. It is time in their life that they should eat what they want, as long as it doesn't hurt medical ills such as diabetics.
This is elder abuse and neglect, sometimes you need to step away and let things get bad, so when you call they can see the neglect and abuse. I would tell them when you call that you suspect Stockholm Syndrome, this will help them look at the protection of the "caregiver " as cover up.
You can not not do anything, this man is living in hell and is obviously frightened of what will happen if he tells what is happening.