This is a standard accommodation that public schools are using for "high needs" students, which includes students who are English learners, those with disabilities, those without reliable access to internet, and a few others on a case-by-case basis. In our building, we are currently in all remote, with a handful of high needs students (mostly El and those with disabilities) in-person fulltime.
In short, this is a perfectly reasonable accommodation that is being used nation-wide with many students with his description. And I'm sure his teachers have noticed the dramatic decline in his grades, so the school may be more open to this than you expect.
