You know, people talk a lot about Nesting Dolls and the fact that Grissom helped Sara, but the truth is, he didn't do more for her than he did for anyone else. Catherine specifically had Grissom's support in a lot of things. When she told a man that his wife was cheating on him, which made him kill an innocent man, he didn't do anything about it; when she worked her ex husband's case, even though Grissom told her not to; when she blew up the lab; when she used the lab to find out if Sam was her father; when she accepted money from her father (yeah, it was from a father to a daughter, but if anyone found out, it could have brought problems to the lab and to her)... In all those times, Grissom risked his job. So, really, although I love Catherine very much, she's just as troubled as Sara (if not more).
Yeah, the team could have problems with their relationship (it would be understandable), but no one can say that Grissom treated Sara better just because he had feelings for her. No one can say he helped her more. That is one thing no one can ever throw in their faces. And while it's true that Catherine has worked a lot, she doesn't work more than Grissom and she doesn't work more than Sara. I don't know if she still does it, but for a long time Sara was the person that worked more overtime.
Everybody in the team knows Grissom doesn't play favorites. He's there for all of them whenever they need him. And I'm sure that even if they don't like what's happening, they will not turn against Grissom and Sara. That's for sure.