What.
No, sorry. What.
Apparently when Mel Gibson was big he was one of the few people who cared about and helped RDJ when RDJ had major problems with substance abuse and was subsequently persona non grata in Hollywood. Now the roles are reversed with Gibson's very public substance abuse problems and exile from most Hollywood roles and RDJ, who is currently one of the most in demand actors, wants to help Gibson.
However, there is most likely someone else on this board that knows more about the subject.