That is a matter of opinion. Younis is a notoriously difficult character who has walked out of Pcb headquarters when the chairman has made him wait for a meeting, he refused to captain in the 2006 ct because he didn't want to be a placeholder captain, etc.
But the police having you believe that one of your teammates killed your coach in the aftermath of the Ireland loss, and your whole team being detained by the police while the whole world thinks you might have been the murderer, and having already lost a few members of your immediate family very recently altogether does take a psychological toll on any person.
You are not in his shoes, you can't decide what his reasoning was, Younis doesn't like expressing emotions apart from anger, doesn't mean we should think he was unaffected by all what was happening. A lot of Pakistanis stopped watching and playing cricket after the loss, is it unfair to say that someone so close to the incident did not feel like being involved with the game for a bit, especially when the group he was given to captain were players he had earlier suspected might have killed Woolmer?