The combined CC between Nautilus and Malphite would hit like a truck; the enemy team wouldn't be able to move for about 5 seconds. If your friend can regularly land himself with Malphite, get you team to pick up a couple of good carries, and you'd pretty much have to feed every lane to lose in Bronze. Wombo Combos are hella fun, too.
I'll give you a little more in-depth information, at least what I give you with a guarantee of reasonably accuracy:
- she's not complicated; playing her is straightforward, as is playing against her. If she wants to go in, she goes in. Her opponent can't do anything about it until she's already hitting them. At that point, if they can get her off of them, they've either taken too much damage to trade back, or they came out relatively neutral, and if they're ranged, can punish her for not getting enough damage down. If they can't get her off them, which a lot of top laners can't, they can either run, or you two can keep smacking each other until one of you dies. The biggest decision you'll probably have to make mid-fight on Irelia is how to aim your Ult to hit the most minions and thus deliver the most heals. This is why Riot will often refer to Irelia as a "ball of stats" design; she goes in and hits things, and hopes she's more powerful than them. The thing right now, is that she often is. She can top and jungle, and has the tools to capitalize on your friend's Unstoppable Force.
- One of the Gods of CC incarnate. Playing this guy, you feel like a one-man army dragging his enemies to their death, mostly because you are. Nobody runs from the Titan of the Depths, and as such, he can snowball even a small lead into a commanding victory for his team. From behind he has a little more trouble commanding the enemy's attention, but he can still make a man regret going to ward his jungle; catch someone out of position and let your heat-seeking anchor do the rest. As mentioned above, pairing this guy with Malphite or anyone else with good AoE lockdown can make life a living hell for your opponents, and a All-You-Can-Eat Buffet for your carries. Just use your trinket to protect against an invade at red buff; you're vulnerable before level 3.
- Even more snowball-dependent than Nautilus, but if you're good at her, you can virtually guarantee some early kills in lower ELOs. Just beware; if you can't handle her skill requirements, she doesn't play well from behind, and becomes reliant on getting multiple picks to get her back into the game. That said, Malphite would probably make it easier for her to get back in the game; trying to dodge a Malphite Ult is nearly impossible if the rockman is properly stealthy about it.
- The great Tank-Eater himself. The beefier his lane opponent, the happier this guy is; he'll out-teamfight them just because he's fighting with a quarter of their own stats on top of his own. I don't know if I can recommend using him in conjunction with a Malphite unless you have some other source of CC, because a long-cooldown Ult and a pillar aren't much. I'd pick him up after one of the other ones, so that you can deal with someone taking out the kind of supertanks that Irelia and Riven have a spot of trouble with. It shouldn't make too much of a difference though until you get up past Silver, so if you like his playstyle, then by all mean gets Trolling!
Hopefully some of this helped! If you have any other specific questions, feel free to ask! Just note that my specialties lie with long-range mages and tanks, which is why I had more to say on Naut and Trundle. The only reason I had so much for Irelia is because I've owned her for a long while, and she's one of the fighters I'm relatively competent with.
Good luck with whoever you choose!
