I completely agree with the PP. If it were me, I would do nothing and just back completely off. There's little you can do in the next couple weeks anyway, and all it will do is stress him and you out.
I would just read for fun, let him pick out anything he wants at the library and just follow his lead. The teacher will do assessments on all the students in the first couple weeks to see where everyone is and then go from there. He is where he is and the teacher will work with him.
Beth, mom to older DD (8/01) and younger DD (10/06) and always missing Leah (4/22 - 5/1/05)