Jacob Joseph Lipenholtz - How is he related to Israel Lippenholtz, David Lippenholtz or Isaac Lippenholtz?

I am trying to learn what happened to my maternal grandfather's (David Lippenholtz or Duwid Lipengoltz) siblings left behind during the holocaust. My grandfather died in 1944. I was told he had 11 siblings. I only know of Isaac and his descendants. How is he related? Who is the source of this information?

Cathy Lisa Schneider