Don't go out and buy a ton of stuff. I believe that you will find if his experience is like many, that at first a larger pad (like those women wear on heavy days) cut in half, cross-sectionally and worn in brief style underwear will do just fine. Then, as he recovers, the light day pads will suffice, again, cut in half. He can carry the pads in his pocket, brief case, coat pocket, etc for when he feels the need to change. It is much easier and less obtrusive to use pads than Depends, he will see very quickly.
So bottom line, brief underwear and pads.