Since his birth, Danny has been expected to also become a rabbi, like his father. This pressure comes from his family and the entire Hasidic community, a rather difficult one to deal with. It appears that he will be a fantastic candidate, given his amazing ability to memorize sections of the Talmud. Of course he has other interests, but he cannot communicate with his father about them as he refuses to talk to him about anything except their religious studies.
Oddly enough, as Danny continues to develop more and more interest in secular subjects, he begins to turn to Reuven's dad as his mentor. This deliberate switching of roles serves to highlight the intractability of Danny's father and the way that Danny feels he must look to someone else for guidance since his father will speak to him about nothing but the Talmud.