Quote 1
"Your uncle was taken away a month ago. You could go to the local soviet and inquire, but I don't think it would be wise." (3.26)
Alex endures some serious hardships to reach Moscow, but the rug is pulled out from under him as soon as he arrives. Now Alex realizes that his entire family is missing, leaving him completely alone in a completely unfamiliar city. Yikes.
Quote 2
"But I can't leave them," Alex said. "It was my idea to come here. I can't leave them now. They are my friends." And, yes, he thought, my family. (12.50)
In the end, Alex honors his family's memory by doing right by Peter and his friends. After all, each of these kids were torn from their families in the cruelest ways possible and set adrift on the mean streets of Moscow. With this in their past, it's only right that they've come together to create a new family.
Quote 3
"If I were head of a government," he said," I would not allow thousands of children to run around in rags and starve, having to steal and even kill to stay alive." (10.92)
It's not until the end of the novel that Alex realizes that the government could use its power for good, but chooses not to. So why don't they? We could come up with a million hypothetical reasons for this, but that's not the point: The point is that it's up to kids like Alex to change their country for the better.