For what i understand they will fork the last version of RHEL and them just keep updating themselves, but i haven't really looked into it to know if that's the case
It's funny because this is a pretty obvious just PR grab by SUSE. SUSE for years now has already provided updates for RHEL. Part of their strategy for selling SUSE Manager is that you can update SUSE and RHEL from it without any vendor lock-in. It's a SUSE repository that provides those updates not Red Hat. It looks like the only thing changing is they'll provide a base image now too.
RHEL is not going closed source. That would be illegal for at least the copyleft components. They provide the full sources in the customer portal which is crap but not the same as closed source.