A search for G* Biber turned up only two results, Gedalje and Gedalja. Based on pronunciations of the time, as well as matching addresses and a birthdate in the range to have attended School #2, I concluded that G. Biber is Gedalje/Gedalja Biber.
I found Gedalje's family by matching addresses. Gedalje had a father (Chuna, b. 1904), a mother (Dauba/Tauba, b. 1902/1904, I thought this was the same person but I could be wrong), and a sister (Estera, b. 1928). Each family member either lived at the Zimmerstrasse address, the Alexanderhofstrasse address, or both (each had two profiles.) All members of the family (except Tauba--no date was listed in that profile assuming it is a separate person from Dauba) were deported on March 15, 1942, during the month of daily deportations to Chelmno. All were deported on transport 29 except Estera, who it says was on transport 2, but I think this is a typo and is meant to be 29, since that's what all the rest of the family--including Gedalje--was deported on.