My Dad passed away within the past year - and we loved receiving the cards from friends and family. Many of them had nice sentiments about Dad, some of them were just encouragement to us (some of my friends had never met my Dad as they were from other areas of the country that we had lived in thanks to military service).
We received some plants and flower arrangements and they were nice. One of the nicest things I received personally was a new tea cup from one of my friends - she and I were always having coffee or tea together when we were neighbors.
As a family we had decided on a couple of local charitable agencies to ask people to send donations to and many people did donate to those, we also received donation cards from other agencies that we had not identified. We were equally happy to see that people were selecting other organizations to support in my Dad's honor.
I think anything you send will be well received and appreciated because you are thinking of your friend and her family in a very difficult time.
T.