tezmand
I have both an iPad mini and a larger iPad. Gromit is 100% right - if you can, hang on until the new models are announced, because at that point you can make a choice as to whether to buy one of the new ones, or one of the current ones (who's retail price will be discounted).
As to which model...it depends on how he will use it.
My mini is great for travelling around with. It works well on public transport. The larger iPad is ideally suited for use around the home.
Also, the larger iPad will have 'retina display', and the smaller one (currently) doesn't.