Margo - thank you for taking the time to keep us updated.
I'm sure it means a lot that both your sister's are there, for your Mom, but also for you 3 sisters. It is a tough thing, I lost my Mom 5 years ago and my sister some 25 years ago....it is not easy, but you and your family will find strength thru each other.
My prayers are with you and your family as you work through those tough decisions, they are never easy.