Vim collaboration with non-vim friend.

Hello, I would like to work on a shared project/document with my close friend who does not know how to use this editor (fair enough). My original idea was to use a vim extension on google docs however the only good one is paid and I'd rather avoid that.

Does anyone have any alternate solutions?
Real-time isn't a priority at all but I wouldn't mind it. I would rather not have to ask them to install stuff on their end or force them to learn too much because they're not very tech-y but I'm more than happy to fiddle around with tools and learn stuff etc (so no git). Ideally it would be possible to edit from the command line on my end but that's not necessary either.