Never turned up

[Torsten]

The sentence is fine as it is because “never showed up” refers to the fact that he has been absent until now. “Never” can refer to the past as well as the future.

show up vs show (He didn't show up to the meeting to day)

“To show up”, in the context of one’s job, means “to arrive”. It is quite common in America. “To not show” usually implies that someone should have come somewhere but didn’t. You would use it if, say, “Michelle” invited “Nicole” to a restaurant, but Nicole didn’t come. You would then ask Michelle “Nicole didn’t show?” Does that help?