My parents haven't properly spoke to each other in weeks. What should I do and who should I talk to about it because it's affecting how the rest of my family behave?

You should stay out of the adult business but be sure to be on your best behavior helping your parents out as much as possible by doing your homework with out asking, doing the dishes without asking, helping with the rest of the family, etc. What your family really needs from you right now is kind words and love.

Perhaps it's time for a family meeting. This may give you an opportunity to give your parents a swift kick into the reality of what is important. This is the kind of "kick" that should start with a hug.

I realize, sometimes couples go through tough times .. Whether it be an argument, a difference of opinion or one did something that deeply emotionally hurt the other .. It's important that they be reminded that your entire family is being affected and "infected" with tension and stress.

They need to be reminded that no matter what they are going through that you and your siblings are suffering unintended consequences.

They need to be reminded that your family is more important than whatever it is that has caused a rift between them.

This is a time to band together .. Not drift apart. Show them how much you love them by standing up and saying "this family is stronger than this" !!  We need to deal with what ever is going on so we can gain traction again and get back to being a loving family.