A coworker created several WinForms-Tools because it was "more comfy" than learning XAML which we usually use for all our sw clients.

Now that these tools are relevant for our infrastructure and some even for the product itself they have to be maintained by others as well.
Note: he tried to use OOP but the result is more like a complete new style of programing . Processes, objects and external scripts in the mix.

Mainreason why noone could know about it: the product manager used him as kind of private dev for some hours a week. No reviews, barely documentation... Now we decided that developing the tools from the scratch is more time and cost efficient.
What a mess...