I cannot question the decision to divert back to SEA for medical reasons. I'm not a doctor and I'm not a pilot therefore I'm not in anyway qualified to question that decision making process (and even if I was, I wasn't there so that disqualifies me too).
I will question how AA handled the diversion after they landed in SEA. It sounds like they could've handled the recovery flight so much better. It's not like they have no employees on the ground at SEA, and it shouldn't have been a surprise to anyone in OPS that they would have a flight full of passengers that needed to be taken care of.