Ah-ha.
They're American Bulldogs....:)
Have a look here;
http://www.bulldogbreeds.com/americanbulldog/photos.html
Notice the dramatic difference in height between "pit" Bulls and American Bulldogs.
http://www.bulldogbreeds.com/americanbulldog/photos.html
Your son got himself some special pups....:)
by jove you are right! The male has a wicked broad chest just like those dogs and is taller than most pit bulls.
So true. We feel a lot better about his wife being alone for a year with the dogs in the house.