Thanks, Adzix.
About whether Catherine will be supportive or not... this is NOT a character slam, but rather my opinion on said character: I think Catherine liked the fact that she helped him realize his mistake and make it up to Sara. I mean, because in the first season, she didn't think very much of her. They did eventually "make up" but it was clear from Nesting Dolls that while they are friendly with each other, there will always be a general feeling of disapproval about certain characteristics the other one has, and those will come out from time to time. For Sara she feels Catherine is oversexual and brings her personal life too much into the cases she works. For Catherine she feels that Sara just likes to harp and throw stereotypes on suspects, drawing conclusions before it's necessary. In truth, though - I think that their prejudices are so much alike that they don't want to admit that, and attack one-another. I mean, both of them like to bring in their private lives and both of them basically say, "Here's who did it because of x, no matter what the evidence is telling them until the end. Catherine generally believes all mothers are innocent, whereas Sara thinks any hint of domestic abuse is the where the answer lies.
But that's why the two women don't necessarily get along - it brings me to a bigger point. Catherine wanted to help Grissom. She wanted to help him, in that scene, realize his fault, realize he's been pushing everyone away and been oblivious to changes in their lives, and that if he can make it up to one person, maybe that will open his eyes.
But Catherine likes being on the inside. I think that no matter what her feelings towards Sara are, and they're obviously very friendly now, the fact that she was kept in the dark about such a huge secret by who is probably her best friend and a fellow co-worker, will make her angry.
Ultimately, I agree with Fogi - I think she will be happy for him in the sense of "he's with someone, he's happy, he deserves that" - but she's always watching out for him. So while privately she'll be happy, I think a lot of her reaction will be bourn of, again, the anger that she was kept in the dark, and the concern for his job and Sara's.
I really really believe, though - that how much of each emotion any of the team gives will be dependant on how the secret comes out. If Catherine is the first to figure it out, then she'll probably be more happy and protective than anything else. If it's revealed by an outside source, I think shock and concern will be the primary emotions most of the team will feel.