For what reason is reuvens father angry with his son at the end of this chapter?

Danny receives acceptance letters from each of the three schools and realizes that his father knows what is happening but does not say anything. Danny tells Reuven how Reb is silent with him, but not Levi or his sister. He also tells how Reb has asked again why Reuven no longer comes over on the Shabbat. When Reuven tells his father how Reb has asked about him, David tells him that he must want to talk to him about Danny and advises him to go on Passover.