Apparently this absent friend broke his back a couple of years ago. Since then, he's become a junkie who stays at home all the time, and cuts his own hair. He also no longer cares much about anything, and has some shitty service-industry job which relegates him to a lower social strata than his friends. The tone of this conversation was about %35 "that poor guy, we all miss him" and %65 "what a hilarious loser who invites our ridicule!"
And then they all sang along to "Killer Queen" and acted it out, and took pictures of each other acting it out.
I'm glad their friend escaped.