Keep them as light and low to the ground as possibly. Based simply on the fact that they're so light with respect to what a normail training shoe is designed for. I like the Tiger-Paw more than the DS-Racer because it is a little lighter and little more flexible in the midfoot. See if you can get to a store where he can try them on and test run them to see how he looks in them. And just keep him in flats from then on.
A few months ago there was a poster who said that his daughter had been wearing the Cubatos (probably the best shoe still available if it fits your foot) her whole running career and had never experienced a training related injury.