We searched the Lodz Ghetto database for P. Zajaczkowski. He was listed as a student in School #20B which had students ranging from ages 9-15 and born between 1926-1932. On the database we found a Perec Zajaczkowski born in 1930 which gave us reason to believe that this could be the student P. Zajaczkowski. We also found two adresses for him which are Kelm 3 7 and Hitler 116, meaning he moved at some point. Although these don't match the address of the school he attended, by looking at a map of the Ghetto we can further decipher whether or not this is the correct P. Zajaczkowski.
It is logical that Estera Zajackowski is his mother beacuse she shares the exact same address as him and was born in 1901, making her 29 years older than Perec. Szulim is most likely the father because he too has the exact same address and was born in 1903, making him 27 years older than Perec. We also found his younger brother Izrael, who has the same address and was born in 1938. Both of his parents were listed as workers and the younger brother was listed as a student.
We also found more information on a Szulim Zajackowski who was born on 27 September 1903 and was born in Lodz. He arrived in Auschwitz on 24 December 1944 and his prisoner number is listed as 15359. We think this could help provide information about where Perec could have ended up but we still do not have concrete evidence.