No idea, but i still had his mail from when i previously contacted him over a year ago. You can also still find his mail on his unity asset store page. So i'm confident that it's his mail.
His exact response was:
Hello,
I'm sorry for my absence and delayed response.
ProUi and Water addon are now open source for the community to take over :
https://github.com/aekiro2/C3Addons
No funding needed on my side.