Anonymous wrote:OP here,
Just a small update. Christmas ended up being a very enjoyable event. Everyone brought their dish and it was so nice to have such a variety of items. It was even suggested we do potlucks on future holidays. Most everyone gave kudos to my brother for suggesting it. All of this was said in front of SIL and the family knew nothing about the email she sent me.
SIL only said hi and bye to me which was just fine with me. My brother said she knows she was out of line and I will not be receiving anymore messages from her. He thanked me for not sharing the incident with the rest of the family. There was no drama and I could not have asked for a better holiday.
I'm glad it worked out in the end. You handled it well. Maybe your SIL had a PMS moment when she wrote the email.