My family life sucks right now

We're in a crappy Italian restaurant in Penn Station right now. My mom and I are overheated and exhausted. She is (understandably) really worn out, and I think she has heat exhaustion.

This is all because we had to go to the Nintendo store on the way from a two day long vacation in Buffalo, all so my sister could meet her friend who lives in Florida.

My sister thinks that she is "a scapegoat" for all of this, (even though this vacation was completely her idea and she dragged us to the Nintendo Store ((admiralty I wanted to go too)). She's yelling right now about how we don't do anything for her.she says my mom brought it up on herself because "we could've taken a taxi" (there was tooons of traffic) and how my mom just hates her...

Meanwhile, my dad and I are trying to be the mediator...

Send help.