What does a hospital committee do? Why do they need to show up?

My dad is going to have surgery in two days. My PIMO cousin let me know that last time he had surgery the hospital committee folks showed up. Is there anything I can do to advocate for him? Or does him having a “No Blood” on file just completely means the decision is final? I presume I have zero say. My mom has previously admitted she’d choose blood for my siblings if they needed it, but the fact that these committee people are showing up leads me to believe she’d still say no for my dad (or siblings). That’s what they’re there for right?! I am worried every day. Either way, I know I’m going to feel fired up that day seeing them, and I really want to say something to these committee people. The way that they think they’re in the right from a science POV is delusional and drives me nuts. I don’t wanna come off threatening but I’m just so worried. I really don’t want them to be there and I will be making that clear to the care team. Appreciate your responses, I faded 10+ years ago, moved countries and got my PhD, so I actually forget the bullshit doctrines I grew up with sometimes, especially this one. I’m reading everything I can to catch up. If I can’t do anything maybe I can find an eloquent, informed way to tell them to fuck off or I’ll just tell them that straight up lol I’m not okay :/