I don't have the tune. It was a wonderful tune, sung very rambly and heartfelt, but it is forgotten. What I did make sure to write down were the lyrics, at least one verse of them. Here's Jacob's song to Kate:
Kate, you're a cutie
And you'll be a cutie 'til you die
When you die you'll be amazed by God
God is a lovely Person
She enjoyed her song very much. Kate responds well to Jacob. Something about him always makes Kate smile. I know it, too. He's a very special boy.