If I am reading correctly, it would seem that you guys are going down next week?? If so, the chances of your brother will not get luggage tags/info packet before he leaves. So, call DME, get him a reservation on the bus. They will need your resort confirmation number (be sure he is listed on your resort reservation!), his flight info. Then when he arrives in MCO, he should just go to baggage claim, grab his bags, then go to the DME checkin desk. He will have nothing to show them, but if the reservation was made, he should be in the system. They will give him a voucher right then and there, and off to the bus he'll go.
The one thing you can do is have them send an email conf. when you call to put him in the system. At least he would have that in hand at the desk.