We're blue hearts chosen because blue was a favorite color of his? If so I agree with the suggestion of using the blue fabrics, but not the hearts. If you feel you can share with your friend either in conversation or with an accompanying card I would share how I thought about and prayed for her and her family (if prayer is a part of your and your friend's lives) and how you focused on things you loved and admired about her son as you made the quilt-I'm sure she will remember your words as she wraps herself in the symbol of your care, support and concern for her. I am so sorry for your friend's loss, you are a thoughtful and supportive friend.