Will question

My Cousin by law recently died and she left everything to my mother in
addition to making her executrix of her will. My Cousin lived in NYC,NY and
the will and most of her assest are located there. She also had my father as
executor if anything happen to my mother prior to my cousin\'s death. My
father died almost four years ago and my mother has dementia. My sister, my
husband, and I have General POA over my mothers business and financial
affairs. Will next of kin have to execute the will or with a doctor\'s
signed statement can I (my sister and husband) act on behalf of my mother?
*Side note My mother can function fairly well but needs to be directed.

[Postman]

poa has an "or else passing" authority in the event there is a failure to act, Who does it name?

I'm not sure I understand you question, but in the will my father is named to handle things if my mother doesn't and no one elsr is named after that.