That would have been a major bummer, especially when he realised. Presumably there was a reduction in masculinising effects on his body too which would have made him feel pretty bad.
I have to say I feel better now I'm taking what the endo had prescribed. I can't put my finger on it, but there was a whole raft of little things that didn't quite feel right on the wrong med. "Well, derr" you might say, but given the right and not right meds are both female hormones it's interesting to see how much better one agrees with me and what I'm hoping for development wise.