What’s happened to Don John? Why doesn’t Benedick want Don Pedro to take care of his brother right now?(Act 5)

Benedick and Claudio reconcile their friendship and tell Don Pedro to find himself a wife so he is not alone. A messenger arrives at the very end and informs them that Don John has been captured and brought back to Messina. Benedick tells them, "Think not on him till tomorrow, I'll devise thee brave punishments for him. Strike up, pipers" (5.4.121-122).