I’ll bet this did not want to leave. I bet they forced him to get the 5 terrorists.
What you just brought up is a good point. I thought the same. Bo comes from a family that holds most aspects of American life in a different regard than the majority. I get the impression that as Calvinists, their social activism becomes a form of offering to their privately known Deity. Sort of like Quakers with an attitiude. Joan Baez comes from Quakers.
I think Bo was upset because “his work” was not yet done. Who knows? Maybe the Dad has been making suggestions on what the Afghans should do to make the Americans a little less comfortable on their land. Bo is going to be a tangled up, emotional mess for a long time, if not permanently.
You will know if the family is about to go off the deep end, if the Mom suddenly decides to separate or divorce the dad. Why divorce after you POW son finally returns home? She might, if Mr. Bergdahl becomes too obsessive in his efforts to mold his son into some imaginary super hero for unsaid causes. Bergdahl wants books and movie rights too.