Lizzy,
First ... our prayers and good thoughts go out to your BBF and everybody around her. WDW does this all the time... as few ago my friend was ill w/ ALS (Lou Gehrigs' disease) and only had a short time to live. I wrote snail mail letters to every executive associated w/ the parks. Lee Cockerells office was the first to respond and offer to help make his trip as magical as possible. He was GM at MK, received a special assistance pass to move to front of line (hardest to secure - they recommend fastpass but I had read about the special assistance pass and convinced them we needed it because we did.), a back stage tour of the living seas including meeting Bob the dolphin. It was really something to witness the joy on both his and his daughters face.
When we returned home, I had several message on my answering machine from different park presidents offices stating they would to do something special. I recommend you do something sooon because it takes time for the request to move up the chain .... also, there is an office that handles things like this and they give free tickets to the terminally ill. Sorry I don't have addresses or contacts but I this helps ya'll. God bless and good luck.
-Chuck