he went to work for a company we were a vendor for
Sounds like he's getting paid to work on the same thing by a slightly different stakeholder.
I'd happily pay $$$$$$ to hire someone with commit access to Cloudflare, AWS or Google's codebase who could fix the goddamn bugs, let alone add new features.
> Sounds like he's getting paid to work on the same thing by a slightly different stakeholder.
This honestly sounds like the sort of thing I'd sit down with the employee, their new employer, and various "Compliance Team" members, and firm up a bit.
Sounds good for everyone.
We get our bugs fixed, $vendor gets to say "Well we have this thing that was developed in-house for BoshNet, that might solve your problem too, it's going to cost you <some comical amount>", and everyone's happy.