At some point he must have had something about him to do all this:
Under Millward, St Helens retained their Super League title in 2000 and won it again in 2002. They also won the Rugby League Challenge Cup in 2001 and 2004 and the World Club Challenge in 2001. In 2001 Millward was named Super League Coach of the Year.(Wiki.)
That's not to say that he's a roaring success elsewhere but he DID have a proven track record, albeit with one club. Not too shabby. So, you can't sack him for lying about his skills, although I appreciate you were stretching the humour.
Can the club afford to sack? How long's he got on his contract?