I suspect Mike your Mate the Engineer will be offered a New Contract, of course on very different terms and it's up to him to accept or refuse. Companies these days tend to replace the non Commissioned (for want of a better way of putting it) with non English cheaper Crews from the Far East bearing in mind there is a surplus due to the number of Cruise Liners that have been have scrapped.
Hopefully if P&O ask for Money from the Government (aka you and I) the Government will remember that the Indian Government refused permission for their Nationals to sail South in 1982 causing all sorts of problems trying to get the vessel's under STUFT crewed, mind you the British newly recruited Crew didn't do themselves any favours but that's another story.
I would have thought that a "Private" Security Officer handcuffing another individual is an assault on that person.
Nearly all of the Shipping Companies are taking advantage of the situation and using Foreign Labour more and more although it has to be said with some Red Ensign Companies have always used Chinese and Indian Non Com Crews, The up side is they made some great Curries
something which I still have at least three time a week barring for Friday which is Fish and Chip day and not to be interfered with
It's a Seadog eat Seadog World today in the M.N. ( Hopefully not in the Curries)