Quote Originally Posted by WarKitty View Post
Just a suggestion, but would some form of video chat be possible? It might be different enough for him to break some of the associations.
This is pretty much what I was going to suggest. A computer chat with or without audio might be different enough. I am pretty sure Alexa can handle calls as well, and screaming at a tube is quite different from calling! Another idea, if you both have a movie service, is to call while watching the movie. The movie might be enough of a distraction to work anyway.

And if technology fails, consider writing him a weekly letter. Hard to do as frequently, but it feels personal for many people. Maybe send a small little gag toy or treat with it.