If you've ever read 1984, or seen V for Vendetta, Soviet-style totalitarianism should look familiar (minus the slick, super-cool costumes and the balletic choreographed fight scenes). It's all about control, control, and more control (did we mention control?).
And what's better for the system maintaining this level of control over its citizens than abject fear, a healthy dose of paranoia, and a willingness to turn on your friends and loved ones (not to mention random strangers on the street) in a heartbeat? Sasha's story in Breaking Stalin's Nose shows us the price that's exacted for living in such a system. Spoiler alert: it's high.
Under the super-paranoid system of Soviet totalitarianism, Sasha can't really trust anyone, and no one can be considered his true friend.
Sasha's dad can be excused for the things he has done (like turning in his own wife as an enemy of the State); he's just trying to survive by any means necessary within this harsh system, and to take care of his son.