The first and most obvious answer to this question is that Misha is an orphan himself. Also, it is thanks to other people on the outskirts of society, such as Misha's friend Uri, that Misha gains an identity and a sense of community.
Misha's nature appears to be a gentle one, and he is kind to all those who are kind to him, resorting to criminal activities only as a means of survival for himself and those that he cares about.
I would argue that Misha was a good friend to anybody who showed him kindness and acceptance. For example, consider the way Misha treats Janina and her family, ensuring that they have food and following them into the ghetto in spite of the fact that he was not Jewish and therefore was not required to.