I have something I want to say about your translation of this chapter, I think you mistake おばさん and おばあさん. Makoto said おばさん, means aunt, so he refer to Haru's mom, not grandma. It's kinda important since lots of people start to talk about Haru's "abandonment issues" because they think Haru's parents left him when he was a kid while in fact they didnt.
But other than that, your translation is really great. I read another translation of High Speed too & yours is the easiest to understand