AITAH: For speaking for someone who isn't a confident person?

A guy in my team at work is great at his job but isn't confident and avoids conflict/confrontation. We do the exact same job but he is far better at it than me. People always come to him to solve their problems in our role because he's so good, but this disrupts things he's already focusing on. You can tell he doesn't want to distracted from what he's doing but will always oblige. A great characteristic but can be taken advantage of, and is, by many of the folk.

So I find myself speaking for him and telling a lot of them to go solve their own problems or come to one of the other members of the team.

Is that an asshole move?

Should be my boss' job but he's useless.