How is it best to handle the family members from "afar" who come in to "fix" everything and criticize what the caregivers are doing?

Welcome to the club. My sister came from overseas to help my mother with a hare brained plan to move her to another ALF that had poorer services than the one she was in. Mother was developing vascular dementia, was paranoid and needed to take her antipsychotic meds, but didn't want too. She wanted to move - her way of dealing with her paranoia. Sis agreed with mother that she didn't need to take the meds and criticised me. I have POA and was not consulted in anything. Sis alienated mother's case worker and staff at the ALF who were doing a great job despite mother's increasing difficulties. I refused to have anything to do with a move. It was a mess. Within a few months, mother was bad enough to require hospitalization, was evaluated and got onto medication and we have just moved her to a appropriate facility. There is a history in our family of me being the scapegoat, so, in a way it was business as usual. Because of the history and some very nasty accusations I have gone no contact with my sister, but make sure my niece has the needed information. This probably looks pretty drastic, and I am not recommending it to anyone unless they are in an abusive situation. I do agree - have as little contact as possible. (((((((hugs)))))) I know it is very hurtful.

They are feeling a LOT of guilt, but they attempt to put it on Dad to relieve their own culpability, and avoid responsibility. Good for you that they live far away. Tell them as little as possible and get on with your own good work.

They came, they saw, they assuaged their guilt. Ignore them. They are idiots and don't deserve your attention.