I am travelling to UK this September with my parents. My mother has power of attorney for my aunt who is in the early throes of Alzhimers. I'm looking into getting some type of trip insurance / cancellation insurance for my parents.

I am not very good at interpreting insurance policies. What, specifically, should I be looking for in a policy that will allow them to recoup any costs if they have to cancel before we leave, or return to the US while there, in the event that something happens to Auntie that requires my mother's intervention?

(EDIT TO ADD) For the purposes of such an insurance policy, is my aunt considered 'immediate family' to my mother (my aunt is my mother's sister)?