I do send home if he's super high and won't go down no matter what intervention I do. I have only one TD1 kid in my school, and one time his ketones and BG was super high. I kept him in my office, and checked him every 15 mins and did what I could, but no fix. I called mother and said, pick him up now and take him to the ER, because he's not going down. She did and they said he was close to be DKA, if not already. He stayed home for a few days and came back better.
That's my instructions from MD as well.