Maybe worth a look at the Crosman range, Mike? Huge choice of CO2 pellet and BB pistols and I guess they're all relatively proven and reliable? I've always liked the looks of that little Wildcat pistol - if only they offered a colour other than PINK!
Not sure how light or easy to handle the Baikal springer pistol might be or the Umarex Buckmark thingy?
Or might he fancy a lightweight rifle? I once had a quick look over a Cometa 50 in a shop and it seemed a lovely, well finished, sturdy yet lightweight little thing that he could probably enjoy for many years.
And then there's the perennial US favourite, the Crosman 760. Cheap as chips, proven and accurate at close range.