Thought I ought to check in to admit that my disconnecting was a total fail.
I did try to set boundaries:
If nonetheless you wish to maintain a relationship, I will communicate with you on your terms as long as you respect my terms:
1) If you tell me that you are writing when high or that you did write me something when you were high, the conversation is terminated.
2) I don't want to hear about your theories about afterlives or realms beyond death or the like.
That's pretty much it, I think.
Right now, he's confining himself to sending me photoshopped images of trees.