Comment by Clubber

I agree. I think it's pretty absurd that the manager was all set to fire him just based on metrics. There's a quote that I'm going to horribly paraphrase that goes like, "when you can measure something, that ends up being the only thing that matters."

At least he asked the author his opinion first.

Having said all that, if he took it upon himself to be a mentor to other developers and didn't do any tickets himself, that seems a bit odd, unless it was explicitly decided/communicated that would be his role. I would think roles like that are half time mentoring and half time doing tickets, but I don't know enough about the team to judge it. Like I said, I'm assuming the manager was new to the team.