Thank you for your suggestions.
I talked to Amy (no, Saltpork, I wasn't talking to myself
), and she told me that they were an elderly couple on a fixed income. He was quite ill and ultimately needed to go into a nursing home. Amy chose to provide services well over what would be covered by our minimum charge (our techs are authorized to use their own judgement). which might partially explain Marie's special feelings for her. And, Mal, you are correct that Amy is indeed a very neat lady.
Following Mal's advice, I just picked up the phone and called Marie. We had a very heartfelt exchange and it is my impression that she was sharing her loss with all those who had meant something special to her and her husband.
A Christmas card...the best gift I could have received.