I know nothing about Kerberos, never knowingly used it. I don't believe it has any connection to OAuth, except they both end up with an access token from an authentication server.
But since Windows uses Kerberos, I assume it can be used unattended without user interaction, which is not the case with OAUth which is designed for interactive web applications.
So I doubt the TRestOAuth component will be much use in implementing Kerberos, although our OpenSSL implementation should handle encryption.
For Windows applications, I would assume there are API calls that will handle Kerberos in the same way that NTLM authentication is handled, but again I've never look at that and have no plans to do so.
Angus