I'm so sorry to hear about your friend. And, bless you for wanting to do a special quilt for her.
A simple but pretty quilt is the 9-patch alternating with a plain block. It is quick to make. My dilemma would be the decision about what fabric to use. Would you want to use one of the pretty pink ribbon fabrics? Would that remind her of the fight she's in the middle of or.... would it help her focus on beating this thing? Or, would you use fabrics that she's commented on .... being so pretty, etc.? I guess you know your friend well enough to know what to use. Good luck on your project.