#2801
↗Not for tech people, I guess. For someone who knows how tech and social media work just a tiny bit this does not make sense. For starters accounts are not bound by/to phones in majority of cases. There are few niche products that are kind of bound to your physical device, but even then they can be moved to another device, if required. Otherwise that's a dead product in modern day.
But even if we assume, that this is the case for this social media (I don't know, think like first days of WhatsApp, I guess), the boy would have gotten the sister's phone, and thus would have heard that messages are coming to that one. Even if that's not the case, why not destroy the girl's phone, and not the boy's? Would she not have a stronger bond to that phone?
That's not all, though, because the account would still exist, so it would still be possible to send message from it. Yes, even if bound by/to a specific device. It would be more difficult, but not impossible. So, yeah, I am not able to buy this premise. Delusion from grief, leading to ignore facts could explain things here, of course, but it still is hard for me to believe in. I think I would be more interested in some conspiracy-driven story where someone is impersonating dead people (which is a thing!), also leaning on "dead web" theory.