He was acting […] playful, not worried, while all the day his insides had been crying, moaning, sometimes screaming. It was like pain, but worse. (1.24)
Much of the suffering that Alex endures over the course of The Wild Children is internal. Don't get it twisted—Alex gets his fair share of bumps and bruises along the way as well—it's just that it usually seems like he's much more affected by emotional suffering than physical suffering
"How long have you been walking?" he asked […]
The boy stared at Alex, regarding his heavy clothing and replying in a deep grunting croak. "Three, four months" (2.49-50)
Wow, that's a really long time. Alex meets a lot of new people while traveling to Moscow, and he comes to learn that his story isn't all that unique. In fact, there are tons of people who have had their lives shattered by the government and are now forced to pick up the pieces, just like him. Unfortunately, that's a lot easier said than done.
Now he, like the others, became wrapped only in his own misery and, for the most part, remained aloof from the other travelers. (3.3)
At first, Alex was a bit disturbed by the way the travelers isolated themselves on the road to Moscow. After a day of walking, however, he understands it a lot better. When it takes every scrap of energy you have just to stay alive, making friends is a luxury you can't afford.
He began counting steps […] but always the vision of the soup came back, floating like a phantom just in front of him, out of reach (3.1)
A steaming bowl of chicken noodle soup has never sounded so good. Here, we see how Alex's imagination makes his situation even worse, forcing him to come face-to-face with the suffering he's going through. Either that or he's just haunted by the ghost of a bowl of soup… The jury's still out on this one.
"My stomach still hurts very much," he said. He looked pale, and dark circles made his eyes appear to sink way into his head. (9.72)
This is devastating. Miska is pretty much the sweetest kid in the world, so we can't think of a worse person for this to happen to. But, as we see throughout The Wild Children, being a good person doesn't mean bad things won't happen to you. There are no guarantees.
The scene that law before them reminded Alex of a picture in The Inferno. (10.6)
In case you're unaware, The Inferno is a book about hell. Not exactly a raving review, huh? Unfortunately, it's an accurate one—Soviet-run children's homes seem more like jails than orphanages.
What had happened had left Alex feeling as if he himself had been struck. He felt a sympathetic pain in his head. (10.17)
As Alex spends more time with Peter and his band, he becomes far more sympathetic to their struggles. At first he was too scared to fully empathize with them, but now that he sees their struggles first-hand, he can finally place himself in their shoes.
Peter had grown quiet since Miska's death […] Occasionally there were signs of the old Peter […] but mostly he seemed to be deep inside of himself. (13.46)
Peter doesn't take Miska's death very well. Although it's easy to underestimate him, Peter truly cares for every boy in his crew and would do anything to keep them safe. Plus, Miska holds a special place in Peter's heart as the youngest member of the posse. We're bumming ourselves out just thinking about it.
"I'm going to go back and… fish with Nicholai" […] Peter laughed, and his laugh […] sounded warm and good to Alex because it sounded like Peter. (13.83-85)
In the end, Peter makes it his life's mission to help suffering Soviet citizens get a second chance. Good for you, dude. Although we don't know exactly why Peter makes this choice, it's very much in line with the guy we've gotten to know over the course of The Wild Children.