Just to add my bit to the discussion on whether or not to mention MLC or not.
Don't.
I did once, a few months in -- first I suggested that it might be depression, as that was something I knew about; when I found out about MLC in general (still not enough, though) I mentioned it to him as well. Once.
Since then he's thrown that back at me several times, saying "you don't think I'm serious, you still think I'm having a midlife crisis". Never mind that last year, at a low point, he said "maybe I'm just continuing my midlife crisis". By then I had thankfully learned to not say anything, at least about that.