Bless your heart, Ritzy. I wonder if anyone could have the right words for Beccah (and all of you) right now. Just BE there for her, as I know you are. She gets to process this in her own way and time. Thank goodness she is expressing the anger! It's grueling as a parent to watch a child suffer, I know. Again, we're here for you.
When my sister's daughter passed at a very young age, so many people just didn't know what to say. My sister said she loves it when people talk about her daughter (still - 27 years later). Keep her memory alive. I remember someone saying "The mention of her name may bring tears to my eyes, but it also brings joy to my soul." Rest in your faith and know that you will all get through this, walking together.
HUGS,
Jan