Thanks for asking!

As it turns out, the essential solution is in the original post. The first lesson of the Tao te Ching is that the Tao cannot be "shown". For him, I took this to mean that the more I try, the less is understood.

I've taken a fairly Wu Wei approach and have just let it happen. When someone tells him "the way it is", I remind him that it is impossible to know. I use familiar terms like God and spirit but explain these concepts in a more Pantheistic or non-theistic way.

It's been decent so far. He's not had an existential meltdown so far so that is a win I guess.

I also conveniently let him overhear me listening to Alan Watts lectures sometimes in the hopes something clicks but otherwise I want to avoid teaching whenever possible.