Does it only have connection problems at the house after the student is logged in or no matter who is logged into it? Do the other students in the house have the same model chromebook? Have you factory reset and reenrolled the chromebook? Personally I'd blame a higher chance of the chromebook being the issue than the home network unless there's a chance the students have figured out how to modify the home network and thus messing with the connection that way. I'd place a even higher chance on there potentially being something wrong with the student's profile on the backend perhaps, maybe their OU is misconfigured.
That said I myself have chromebooks randomly dropping off the wifi which I still can't figure out but our current WAPs and their controller are all EOL and are being replaced soon. I figure there's a high chance something is misconfigured or the old WAPs are getting overwhelmed which the new ones would hopefully solve.
edit: I'm also curious whether the chromebook has the issue no matter where it is in the house.
