Hey Shrader,
I'm very sorry.
My mom was a teacher and when she passed a year and a half ago, it was a note like yours from one of her students that I cherish most. She loved her students and she was an awesome mom, but when she was gone it was so final it seemed. It was notes afterwords like yours that were so comforting. they said in essense that the lessons each student learned meant so much that in spirit she lived on. Don't fail to communicate to the family your feelings . It really means a lot.
Take Care,
Steve