Collaborating with siblings

My husband's three sisters live near his parents and are actively involved in caring for his father who recently  experienced a sudden cascade of medical issues that have  required serious attention.  They are doing a wonderful job supporting each other and sorting out their respective responsibilities for the folks.  It seems our best contribution is to make sure we stay in touch with each of them and pointedly ask what they need from us.  If we were to confine our communication to my father-in-law we would get a much rosier picture than the one we see from his daughters' perspective.  It really helps to stay connected to everyone.