"Enough!" Harry said calmly and firmly to the both of them. "We can discuss this another time, but now is not helping. We need to find Sirius and make sure he is all right and not among the dead, then we need to set up means to get statements and James you need to write a full report about what happened here today."
He agreed with Snape about the cloak, but he would not say so now, and he would not stand around hearing his son get insulted, whatever the reason was. For everyone's sake though, he thought the best way to end it was to end it quickly.