The Coho is a pretty good fly to stick to! I would also recomend looking at a variation of leech patterns and other streamers, purple and red seem to work well! If he is not planning to fly fish and is using a spin or bait casting reel, I would stick with the Coho. Because the method used to when fishing a fly on a spin caster, is the fish will let the line slide through their mouth thinking that there is bait on the end. And when the time is right you snag the fish.
Hope this is helpful information!
BC