That won't be an easy thing to work out, short of reverse engineering that BOB :/

Have you got anyway to get the config of the computer that died?

I think at this point, I'd suggest ordering one of the generic 5-axis CNC Breakout Boards from eBay. And just checked, there is a solitary one available via Amazon Prime - https://www.amazon.co.uk/Fasizi-Brea...dp/B09Z29TYNL/
There are a few resources for those generic BoBs, which removes having to guess what pins are required to get the Tonman BoB working.