I think one major draw for overseas managers (and players) to come to the PL vs other countries is that the media isn't as obsessive here as overseas (particularly Spain and Italy) and you won't get reporters with telezoom lenses spying on you, chasing you around, checking through your recycling bins etc. Likewise the Brits tend to leave celebrities alone to more of a degree than other countries, plus if Man City, Arsenal or whoever lose a game it's unlikely that a bunch of club ultras will storm the training ground to have it out with the players or send death threats.
If his wife and kids are happy here then why uproot them and take them to a potential powder keg environment elsewhere, particularly as he gets on so well with the club hierarchy and doesn't have to get involved in tin pot dictator-esque politics like you get with the presidents of Real Madrid and Barcelona.