They tell us what happened to them. They tell us what happened to her POS brother, but they don’t tell us what happened to her!
Yes, that true. Perhaps due to the media's failure, perhaps information not easily accessable. We don't know the story of her life, but I presume that she's Maria (Cornet) Sixma, honored by Yad Vashem with her husband, & son Frederik Frits as amongst The Righteous Amongst the Nations, so history may remember. Unfortunately little more information, though obviously it's documented at Yad Vashem, just not on the web. Not as important as her SS brother I guess, honored to this day on Nazi sites. I suspect her families story would be of interest, but we can't find much other than her brother.