He would have considered his actions carefully,taken all necessary precautions and then acted.
It was a few years ago now but in my airline the captain had a truncheon at his disposal and full authority to use it. Wasn't it just a few years ago when a BA flight engineer armed with a C02 fire extinguisher went down the back to subdue a recalcitrant idiot. With the extinguisher pointed right in his face the man quickly sat down.
On another occasion in my old company, the female FA's were getting felt up by a drunken bush-lawyer Pacific islander on a flight Hong Kong to Guam via Taipei. . The next port of call was Taipei. The captain decided to sort out the islander personally as it was obvious the FA's were unable to do so. He shirt fronted the islander and said unless the bloke sat down and behaved himself he (the captain) would arrange for the Taiwan police to meet the aircraft and take way the islander to be tortured. It was no empty threat and it worked a treat.
It is such a pity that the rules and regs in theory prevent the captain from leaving the flight deck and thus leave the flight attendants to get beaten up by some drunken bum while the flight crew lock themselves safely behind the door and pretend not to know what is happening down the back. The FA's can only hope some passengers will come to their aid if things turn nasty while the flight crew cower behind their locked door.