So...uh... If he thinks my parents not calling him is proof that they don't care, um... they've evidently been putting a much higher effort into staying in touch with Bro2 than they do with ANYONE ELSE. Likely because they are concerned about him AND because he doesn't get in touch if they don't.
But if Bro2 is acting annoyed or frustrated or like he doesn't want to talk when Dad calls him, of course Dad is going to back off.