The scene at the end of this chapter is big feels. It strikes home for me personally, having known bullying and how cowardly most bystanders are. All the instances of people going 'not my problem' when an issue is right in front of them add up to a trail of damage across lives, and hypocrisy when the former bystanders someday are themselves lost without help that could have been easily given. Humans suck.
Rei, offering what may be the rest of your life to someone isn't a small thing... It's touching how he doesn't consider any implications, just that his friend proves there are people good enough to have not let him suffer and thus she's a very special existence to him. The scene was also beautifully done in the anime version.
Geez, this manga and A Silent Voice really deliver some gut punches by dwelling on lonely characters.