American Airlines participates in the "Make a wish" Foundation - this is normally used for terminally ill kiddies to visit DisneyWorld, but they may well have further info for you. I don't have their contact number to hand, but if you call your nearest AA office in UK they may well be able to help. Failing that, try calling the DFW Flt Office at (usa) 1-972 425 5151 and ask for any contact info they may have for the above - explain your situation.
In addition, I am more than willing to donate one of my buddy-passes to assist; e-mail me for more info, please. There may be security implications, believe it or not, that's the US TSA for you...