Hmmmmmmmmmm
Hmmmmmmmmmmm
Hmmmmmmmmmmmmmmmmm
We don’t have much actual information, other than that he does decide to risk his life to save Yomo from Souta/Furuta/Kichimura’s plan (alongside Itori), even though the Clowns are technically Furuta’s co-conspirators. So Yomo and Itori are clearly two people he definitely cares about.
I actually think that he is probably alone and scared because he’s harboring an enormous secret. Perhaps he’s an escaped garden ghoul, as I’ve seen theorized but can’t recall where I’m sorry. Perhaps he’s one of the kids seemingly spawned from the enormous kagune below the 24th ward, though they more resemble Itori than Uta:

Orrrrrr, there’s a growing body of evidence that he may be the original One-Eyed King, a la @midnight-in-town’s theory and Ishida’s suspicious birthday art.
If that’s the case, he’s much, much older than he appears, epically failed at his original goal to help ghouls, and also, is being hunted by his Washuu relatives. I imagine that could conspire to make him very lonely. I mean, how do you tell people all that?
But for now, dear Nonny-Mouse, I earnestly await more Uta reveals alongside you. 🙂