Timing chain tensioner

my timing chain tensioner broke inside the timing chain housing cover.  A local macanic who was repairing my car has suggested metal & plastic from the broken tensioner have somehow gotten out of the sealed housing cover and into the sealed top cam section of the engine and is suggesting that he will now have remove the cams and a load of other parts including the headlights raidiator etc etc to flush the engine to make sure none of theses bits get into the cams. he has then suggested since he has to remove theses parts to get the cams out he may as well replace the timing belt and water pump. 

A. Is he taking the !Removed! and having my life and the broken bits cannot get out of the timing chain housing cover which is what I think!! 

B all above is true (lol)

thanks