The name Matl Bergfrojnd unfortunately doesn’t exist in the Holocaust survivors and victims database nor does google recognise it anywhere on the internet but on the children of the lodz memorial research project website. Google suggested spelling Berfreund, but that name turned up results of people much older than those at school #5 where Matl Bergfrojnd was. I decided to input only the last name as a fuzzy search and still found nothing until I searched “Bergf*”, which led me to names spelled Bergfrajd and the listing of a person born in 1930 (appropriate for school #5) was a boy named Motel Bergfrajd, which seems to fit fairly well.
I was directed to a website called Jewish Gen and ended up creating an account there so that I could view their records. Upon searching for the Last Name Bergfrajd I found three entries aside from Motel with the same address. The sibblings I listed were born 193 and 1937 so I assume they were sibblings whil the other born in 1898 must have been the mother. Gender was listed as F for all three. These records were found in the "lodz ghetto list" in the "holocaust database" on the jewishgen.org website.