Definitely go PE for simplicity of use and sharpening. If there's a concern about spending too much money on a knife that won't get used much, but you want to get your brother something that's high quality, then something along the lines of an Endura should work nicely.
If the idea is to get something dependable that'll take a licking and ask for more, and price isn't an issue, then the Military, Para-Military, Manix, and Chinook are some possibilities to consider.
A good knife sharpener is a must as well, so perhaps a Spyderco Sharpmaker might be nice, if you feel he'll make use of it. Plus, the Sharpmaker sharpens other things besides knives, so it would be quite useful around the home or campfire.
I've included some links below concerning field test reviews featuring the Endura, Military, Para-Military, Manix, and Chinook. This'll give you an idea of what these knives can take and still perform.
http://www.cutleryscience.com/reviews/endura_pe.html
http://www.cutleryscience.com/reviews/m ... _s30v.html
http://www.cutleryscience.com/reviews/paramilitary.html
http://www.cutleryscience.com/reviews/manix.html
http://www.cutleryscience.com/reviews/chinook_II.html