About handle bars: Those old fashioned "hunting daggers" have huge handle bars because everything becomes slippery when covered in blood (or so I'm told).

That being said, a protruding knob between the edge and the fingers should be plenty "handle guard" for your brother. Something like the handle on that K-BAR 7. It also looks like the scales on that handle can be shaped with a rotary tool to suit individual hands. (That handle look a bit too squarish to my liking, but it is kind of hard to tell from internet pictures... )

6 inches is too big a knife for me, so I'll express my ignorance on those and wish you luck finding your brother a nice present. Remember, it doesn't have to be perfect - it just has to be good enough to not be left home. The features of a "perfect" knife is something your brother can tell you once he has used that knife for a couple of years...