Lovely sentiment and congratulations. Sorry you have gotten few serious responses. Mozart’s solo piano works should definitely be on your list. Just about any of them; but, earlier ones, composed when he was himself a child may resonate especially. You may find this of help:
https://www.wqxr.org/story/mozart-solo-pianist-part-1/
And for both the little one and a Jazz inclined grandpa, Chick Corea’s “Children’s Songs” are lovely pieces with much more depth than meets the ear at first:
https://youtube.com/playlist?list=OLAK5uy_lVpu7PVEUoTtBr_9Wc9RH-6l_Q1waXoq4
And, of course:
https://youtube.com/playlist?list=PLjb5kMzP2zomz-fvIiD5XpY-QR0IrWwWn
https://www.wqxr.org/story/mozart-solo-pianist-part-1/
And for both the little one and a Jazz inclined grandpa, Chick Corea’s “Children’s Songs” are lovely pieces with much more depth than meets the ear at first:
https://youtube.com/playlist?list=OLAK5uy_lVpu7PVEUoTtBr_9Wc9RH-6l_Q1waXoq4
And, of course:
https://youtube.com/playlist?list=PLjb5kMzP2zomz-fvIiD5XpY-QR0IrWwWn