Enjoy it, whether he shares your diagnosis or not.
I don't remember a kid, NT, AS, or otherwise, who didn't enjoy knowing and spending time with my AS father.
Someone who can relax and enjoy being with a kid is a rare find, and a great treat, both for the adult and for the kid (and, for that matter, the kid's parents).
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"Alas, our dried voices when we whisper together are quiet and meaningless, as wind in dry grass, or rats' feet over broken glass in our dry cellar." --TS Eliot, "The Hollow Men"