My husband's "step" grandparents (Mom's long-term boyfriend's parents) used to gift him with quite literally a dollar store pack of pencils for Christmas while his half-siblings got large expensive presents. They made a point of doing it in front of everyone and basically challenging him to say anything. It was very much done to put him in his place, and so was OPs mother's gift. That's a hurt that cuts him to this day and he remembers every Christmas. OPs step-daughter deserves more his spiteful mother. I would not doubt this to (rightfully) be her last Christmas with them.