I'd say ignore the e-mail. It doesn't really invite a response at all. If you really feel like responding, maybe a quick 'Have fun' and leave it at that.
I think your H still needs space and time- he probably can't stick to the schedule partly because he's depressed, and maybe partly to see how you react when he doesn't stick to a schedule. Would not reacting be a bit of a 180?
I'd go to Dublin with no expectations at all of seeing him. That'll get him thinking more than anything else. But also don't expect any quick changes. DBing takes time, and each situation is different. With your H being depressed the situation is more complex than others, so things won't get resolved until he's sorted himself out. Difficult to put a timeline on that.
Glad the weater there's good today. It's cold and wet here- typical England!
