Gender: boy
School:
School #14B
I found Jozef Apt born April 12, 1930 and he lived at Talweg 4 flat 11 and Talweg 7. I'm pretty sure this is the Josef Apt that signed the album because he would have been the right age.
I found the following people living at Talweg 4 11. Rywka Apt born 24 Sept 1891 (mother) Emanuel Apt born 22 July 1925 (older Brother) and Teresa Apt born 2 Aug 1927 (Older sister). I couldn't find anymore information on the Apt family.