I'm sorry I missed this discussion. As always, a disclaimer: Laws differ and it's not my main field.
I'd be shocked if there's any law in your state that requires notification of any bequest or lack thereof until the person passes away.
Not only that, but say, out of kindness you DO tell him. Then, say 10 years from now, he's wracked with grief and remorse over having cut you off and tries to re-connect. Would you ever be able to tell yourself it was for any other reason than to get back in the will?
No...unless it's a requirement (which I greatly doubt) I would not notify him.
This is generally what's required.
You don't have to be mean. You can be quite gentle. "To my son Gone Boy, who I always loved, based upon his great success financially, no monetary bequest is made. He shall receive [fill in the item], in memory of happier times."
In any estate-planning, a lawyer is always the way to go.
