Gender: boy
For M. Sochaczewski I found Majer Binem Sochaczewski born 1925 and lived at Hanseaten 8 flat 45 and Albert 16 and he was deported with transport 7.
Oops, I don't know how I missed Moszek Sochaczewski. I found him living at Hamburger 39 flat 1 and Narutowicza 34. I also found him listed as Moszek Sochaszewsi born 1927 and living in the same addresses. Either boy could be a match for the student.