YouTube memorial for Sara Sophia
https://www.youtube.com/watch?v=MbE0Zaq14tQ
YouTube memorial for Marcus Kellerman
https://www.youtube.com/watch?v=pd9vM5pJU5U
YouTube memorial to their son, Meijer Kellerman (English spelling: Mayer, Hebrew Meir)
https://www.youtube.com/watch?v=fvjQv0pH138
Their son may have been named after his grandfather (although at the time of his birth, he was alive). Meijer Kellerman was also tragically murdered at Sobibor in 1943.
YouTube memorial video: https://www.youtube.com/watch?v=gYFnv1H81hI