There seems to be a chronic shortage of good people for Sasha to admire or use as role models in Breaking Stalin's Nose. His two main heroes are his dad and Joseph Stalin. It takes him a long time to get over his fanboy worship of Stalin, and along the way he starts to question everyone that he initially admired: his dad, Nina Petrovna, and the school's principal, Sergei Ivanych. That's because admiration in the novel comes as blind ideology (basically, what you've been taught to believe) rather than any individual judgment of people's good qualities. Questioning this and seeing how his own dad falls short is a hard lesson to learn, but Sasha starts to get it by the end of the book.
There are no true heroes in his book. Everyone is just out for themselves and trying to survive, which is basically the opposite of "heroic."
Out of all the book's characters, Vovka and Finkelstein come closest to being heroes, since they both put themselves in clear danger for the good of others.