If you have an order of custody of the child, then the grandmother would not be able to enroll the child in school (among other things) because she would then not have an order in her favor. You could, however, have an order crafted which gives both you & the grandmother "joint custody," while specifying that the child will live primarily with the grandmother.  -- David Bliven, Bronx Co. Child Custody Attorney (www.blivenlaw.net)