My take.
OBL was in Abbotabad.
The Americans found out he was there. Moments before the raid, Kayani was called and told to stand down the radars and warning systems to allow the American Special forces in.
One of the helicopter that went down was probably downed in the ensuing confusion. Someone from the Pakistani side downed the helicopter.
The Americans killed OBL, Kayani was caught with his pants down, but the only salvage he could make for public regurgitation was they downed the helicopter.
The Americans, for Pakistani service rendered, did not proceed the matter further that whether it was elements within the establishment that harbored OBL. Most likely, the establishment did not. The intelligence was too busy in Waziristan and FATA.
All in all, an embarrassment for Pakistan. And they arrested Afridi and refused to give him to the Americans, to avoid further embarrassment. Few years down the line, he’d be quietly shipped to US through backdoor deals and in exchange for mansions in Florida / Houston to the Generals.