Write a story

I tried automatic writing many times, all with obvious results, my inner self responding. However, last night something weird happened. The letter began with 'Dear Santa' which was no way in my mind.

The writing wasn't even like my own. Strange 'A's. Creepy.
Sissie, my twin left the room slamming the door, locking herself into the bathroom. She was gone for hours, eventually after a lot of banging and pleading she opened it and returned to sitting on the carpet, large bathtowel over her head, rocking back and forth, humming.

She is autistic. I knew what was wrong. She was scared.

Later that night after I eventually got her back to the bedroom she pulled out the notepad she normally kept under her mattress hidden from view and showed it to me.
Letters all starting 'Dear Santa'

She couldn't write. Or so I always thought.