Biggest Plot hole..
No one else seems to have noticed this, so perhaps I'm missing something, but, Vin Diesel got the Dad killed in the start!
So wouldn't it be illogical for them to assign him to protecting the rest of the family in the first place, look how well that went with the dad!
And even having said that, the wife does not display even the slightest bit of resentment toward him for this, and neither do the kids.
Wtf..