I have a Downs grandchild. Everything you say is so true. Has two normal siblings.
My sons often serve Mass with a boy in his teens who has Down’s Syndrome. He has four older brothers, all in the military, and often brings G.I. Joe figures to Mass when he’s not scheduled to serve, because they remind him of his brothers.
It’s inspiring to watch him at the altar, because, if he’s not busy handing things to Father, he just gazes at the Crucifix with the most joyful and loving expression. It reminds me that every one of us is broken, “disabled” in some way - it’s just that some can pretend they aren’t because our problems don’t necessarily show on the outside.