+1 for the 870. They have a 100th Anniversary edition which is great looking:
Model 870™ Wingmaster® 100th Anniversary
or you could go with the regular wingmaster:
Remington Model 870™ Wingmaster®
Although your dad asked for a pump, he might like a semi-auto. They tend to tame the recoil of the big loads. For that, go with the Remington 11-87 Premiere if you can find one.
One nice feature of the Browning BPS is that it is a bottom ejector, so both left and right handed people can shoot it.
Whether you go with one of the Remingtons or the Browning, they will all shoot the light 2 3/4 loads up to the 3" magnums.