I would tell her you have given her quilt much thought and just to be sure you asked some of your friends who quilt. BUT, don't mention possible health problems. Copy a few of the answers from the board then suggest a change and offer to help so she doesn't become over whelmed with the project. Maybe over a cup of tea and a chat you will be able to find out about why she was sick. Could be a medication, could be age, do family members understand that she may be having problems. Does she need a little extra attention where family may want to check in on her more.
You sound like a very nice caring neighbor. Just go slow and I am sure she will be so happy for your help and friendship.