Sublime merge would have been a good suggestion in this scenario. It's UI uses standard git terminology and concepts, so you'd have been sneakily trainig them in the command line whilst they used the UI!
This is also why there was so so much fuss about git GUI client, there were looking for a golden hammer, a GUI that would do everything and anything.
Sometimes I read these things and end up saying to myself "Wow, that company just literally hates being productive"
The more tools people are allowed to install and use, the less standardised software development. Meanwhile we didn't even have common source code formatting pattern and single Java class could be formatted with tabs, 2 spaces and 4 spaces.