Well Mr Boxer ended up calling. Apologising, saying he felt awful etc. He's got a serious head injury apparently. I steered it in a lighthearted direction. It doesn't actually matter - his health obviously does. I can understand why he wouldn't want to meet under circumstances of serious pain and injury - but he obviously should have spoken up about this beforehand before suggesting to meet in first place.
He's mentioned meeting again but doesn't blame me if I'm reluctant - I told him in no uncertain terms, let me know if and when you're next in town, if I'm free, we can try to meet. End of. Nothing more complicated. My expectations are zero.
At least we've left it on a positive note. There's enough unhappiness in the world. I'm glad he apologised and I hope he's going to be ok, health wise.