Good news, I just gat a call from my friend with the LFS and he called the guy and is going to pick him up. He said once he explained what happend the guy was very understanding, my friend is going to get him another fish though probebly not another RD. Turns out the guy who bought him liked the way he looked but didn't know anything about RD's and figured he was about the same size as his Oscar so they would get along. So he put my RD in a 90 gal with an Oscar that has been pinned into the upper corner of his tank all day! So it looks like this will have happy ending, for everybody.
As far as a back up plan goes I only have a 30 and 20 gal sitting around and since my buddy has a fish store I thought that would be a better alturnative, live and learn but at least he'll be home on Tuesday in a brand new 90 all to himself.