So sorry to hear about your Mom's Alzheimers, it must be very difficult for your entire family. I think I would measure the quilt top and see if you can use it as is for a bed quilt, otherwise, I think I would pull one of the colors in the quilt, such as blue or gold, although a border might not be necessary. I'm sure that helps a lot. Not. What a wonderful treasure to find, and finishing it will honor your Mother.