All reality TV shows , from BB to Pop Idol etc., have one thing in common, all participants sign a contract with the production company allowing them to use whatever they want about their public and private persona.
These performers have been with XF for some months now, they will have come into contact with various people connected with the production company and also PR companies.
There may have been times when some or all of the acts have felt the strain, and perhaps at times like this thay may require and receive some counselling, this may be provided professionally, or, as I suspect, somebody's shoulder is offered to cry on. Whatever the reason, we can't expect these acts to not say anything to anyone about their private lives, that's an impossible demand.
Who knows if Chico's friend may have had a particularly harder time with their illness at some point, and maybe Chico was down as a result or whatever, and needed time away - we just don't know. But I know about what TV productions will do to get publicity for their shows, they all do it, and of course, it helps an awful lot with the script for Saturday. I mean by this, that for the producers, Chico singing Hero, will create a context that will surprise and engage the audience. And that is the main job of this show, to keep the viewers coming back for more.