Which faction do you like the most?

If he's more experienced, then the chances are indeed slim. And the race doesn't really matter (all races are balanced). Play as the one you like the most, know and use the strengths and weaknesses of your own and your enemy's units!

I disagree that they are all balanced. The rune magic of the Dwarves is just too powerful. Besides, they can also develop regular magic well. But the creatures of the Orcs are generally weaker than those of the Dwarves! A Cyclops is absolutely no match for a Lava Dragon, and an Orc Warrior is much weaker than a Bear Rider. Besides, the Orcs have no magic, only a war cry and that's it.