I'm really not sure what his problem is. I play a level 34 warrior, and I've found questing and grinding to be pretty simple, really. I solo most of the time. Our equipment is pretty similar, too, (Mine: http://armory.worldofwarcraft.com/#character-sheet.xml?r=Dragonmaw&n=Bladebiter) not too fancy, but not terrible either. The one thing I notice is that his strength is a little low (I consider myself to be on the low end for my level), and he definitely needs more stamina. He should look for more of both. If he can get them, he should be fine. For example, I am pretty confident in fighting something up to 3 levels above me, and I can take down 2 equal level mobs with no problem.
The thing that I've found about warrior, is that once you get in over your head, it's really, really tough to get out. So the key is to not get in over your head. Use a ranged weapon for pulling, and look before you leap.
I assume your friend knows that already, so here's what I'm doing right now to level. I'm questing in Hillsbrad and finishing up those quests, then moving on to the ones involving the Alterac Mountains and Arathi (Vale, I think). If I wasn't doing that, I would be in Desolace killing centaurs (questing). I would highly recommend finding a good area and questing, as opposed to just grinding.
From reading these boards, it seems like dual-wielding is very difficult until you get some higher level gear, so he might also want to consider picking up a big two-hander.
My fighting tactics are pretty basic. If the enemy is isolated and easy (no more than 2 levels above mine), I just charge and alternate Thunderclaps and Sunders, mixing in a Hamstring or Demoralizing Shout.
If the enemy is in a group, I pull with a bow. If more than 1 comes, I make sure to open with Thunderclap and Demoralizing Shout, then Cleave to my heart's content. In a bind, Intimidating Shout can help give you some breathing room.
If the enemy is tough (elite, or 3+ levels above mine), I charge, Thunderclap, Demoralizing Shout, SunderSunderSunderSunderSunder, Thunderclap, then start Slamming.
Slam is actually really good if you have a slow weapon, as it is faster than your normal weapon swing. I stay in Battle Stance most of the time, as Overpower is awesome and only available in that stance. Always use Overpower whenever it's available. I switch to Berserker Stance only if I need to intercept or break fear a second time (after Will of the Forsaken).
Battle Shout should be up all the time.
If you need to run, Hamstring and Intimidating Shout are the two tools you have, so learn to use them.
That's about all the advice I can offer. I haven't really had any problems leveling my warrior, and I've only been playing the game since the end of March, so hopefully this helps a little.