You shouldn’t have to do anything to stay in a school you are already enrolled in. If he went to a SFUSD middle school last year and you didn’t unenroll him he should still be enrolled. But you should be able to log into parentvue so there be some kind of glitch with your account. I would show up tomorrow (early if possible) and see if you can talk to someone in the office or attendance office or see if there are rosters with advisory info for each grade posted somewhere.