All jokes aside, despite the fact that multiple sources of canon tell us that Maui struggles with being empathetic and understanding where others are coming from when it comes to their needs in the way of emotional comfort, I'm gonna come out and say it: Maui is actually very good with being empathetic, but only in a very specific kind of way that only resonates with Moana.
(some fun analysis, please don't tag as a ship)
Here's the thing! I've been listening to Can I Get a Chee-Hoo? a lot lately, and the more I listen to it the more patterns I started noticing, and the more you unpack those patterns the more you start to understand why it worked to lift Moana's spirits, despite her being unreceptive to everything else he tried.
Namely that he went after her sense of identity.
Self-identity has always been hugely important to her. He's gotta know that better than anybody, given how many times she told him in the original that she is Moana of Motunui, and he *will* board her boat and sail across the sea, yadda yadda, you all know the rest.
And here's the thing! That's not even remotely close to the only time where the importance of one's identity comes up! (He, uh, wasn't there for one of those times, because one of those times was right after he took off and left at the result of frustration with his own sense of identity, but I digress for that specific situation), but do you know what the important thing to note about those other times is?
Both of those other times, she was reaching out and trying to comfort someone else by reminding them about their own sense of identity!!
I talked briefly about this years ago, but there's a tiny scene in the novelization for the first movie that's omitted from the movie itself. It's right after Lalotai, but far before Moana gets Maui to open up about his issues with abandonment. If I remember right, he's being a stubborn pouty mess about his hook not working, refusing to even get back on the canoe at all, and the way that Moana gets him to comply is with a speech that goes somewhere along the lines of "We will make it all the way to Te Fiti, and you will defeat Te Ka, and I know that because you are Maui." It's a tiny gesture, and nowhere near as sentimental as her later "You are not nothing, and maybe the whole reason the ocean sent me here is to help you see that”, (also from the novelization), but it works, because in that moment all he needs is that gentle push and a reminder of the strong and powerful person he sees himself as. It's not about how she feels about him, it's about him needing to have faith in himself. That's what works!! That's what motivates him to keep going.
The reason I bring all of this up is that Can I Get a Chee-Hoo? is his way of doing the exact!! same!! thing!!
The first line in the whole song!
You're down in the dumps, you think you're way off your game, but you can turn it around, just remember your name!
He's not calling out to some scared kid, he's calling out to the Moana he knows, the Moana who's unafraid to shout her name from the mountain-tops and not care who hears her! The Moana who stood her ground in front of the very same lava monster who took him down without flinching once! Maui doesn't need to say he's proud of her or that he believes in her, not directly, because this is his way of saying this is not who you are, you know who you are.
The whole song is calling out to that pride he knows she has for herself.
Who are you? Who are you gonna be?
He's not looking for a dramatic, over the top answer. He's only looking for things she already knows. She is Tautai Moana of Motunui, she's the human who restored Te Fiti's heart when he couldn't. She knows who she is! But she's lost her way, just as he had once, and this is his way of helping her help herself out of it. He makes a joke about their roles being reversed for the sake of quid pro quo, you helped me so now I'm helping you, but whether he realizes it or not, he's using her own words against her! "I know who you are. Do you? Do you remember who you are?"
He sings her praises, (literally), but none of them are exaggerated or overly boastful in the way he sings his own praises! (also literal). She's legendary, she's going to make history, but oh, you actually already did! I know your legacy! Everything beyond I know your legacy and your destiny and I know that you're great is only hypothetical to build her up! He never claims that she's going to destroy Nalo, or that she'll singlehandedly do anything impossible for a human, it's all can you imagine the stories they'll tell about you? because he knows that's what's important to her!
The reason it works is because it calls her to pick herself up, just as she had done for him. In the novel, where a song obviously needs to be replaced, it all boils down to the essentials of "...I’ve been low before, and I couldn’t see my path. And someone came along who I underestimated and she lifted me up. Someone I don’t want to underestimate herself right now.” It works because it's less about come on, we can fight this guy! in reference to Nalo and more about come on, I know you can believe in yourself better than that!
And perhaps the most important thing of all:
It's established in the novelization pretty early on, even before they're reunited, that she misses him and all of the teasing and all of the nicknames that comes with him (not that she'd ever admit it out loud, she'd rather be caught dead). She's used to Curly, that name is second nature to her. She's annoyed by princess, but will still respond to it if he calls her by it. They're affectionate nicknames, by all means, but she knows Maui, and she knows he tends to fall back on teasing and jokes and avoiding the heavier topics.
When he calls her Moana, she knows that he's not messing around. He's not teasing her. There's genuine, serious truth to what he says.
Throughout the song, he uses nothing but her name. C'mon, Moana, you know you can do this. It's a lot different hearing I have faith in you, you're the bravest wayfinder there's ever been when it's attached to her own name. He isn't teasing her anymore, he's genuinely trying to reassure her of her identiy and her inevitable legacy and if all else fails then that's what I'm here for.
It works for her because he's demonstrating empathy towards the one thing that's more important to her than anything else. That's how she knows he cares. That's how she knows he listens.
tldr; Even though Maui isn't great at the whole understanding and empathizing with humans thing, the reason he's still able to resonate with Moana is because he's able to empathize with her in a way that others may not have been able to.