OP tells us that Becca suffers from celiac disease and a severe dairy allergy that she carries an epi-pen to manage. OP also says that while she isn't a chef, she has taken lots of different cooking classes and enjoys “making elaborate meals” for her family.
Recently, she hosted a five-course dinner for her parent's anniversary, to which she invited Chad, Cheryl, Becca and her sister, her sister's boyfriend, and their 8-year-old twins.
She laid out from the start that she didn't feel comfortable cooking for Becca as she was afraid she'd include something in a dish that would set off an allergic reaction. OP also says here that she suffers from ADHD and couldn't trust herself to finish a meal that Becca could safely consume.
So, OP found a restaurant specializing in gluten-free courses to help with Becca's celiac disease and ordered her a full meal to complement what she was preparing for everyone else.
When it was time for everyone to eat, OP said she served everyone and could see Cheryl looking at her daughter's plate with a “stony face.” OP said she saw Cheryl whisper something to Greg before Greg asked if they could talk in the kitchen.