Ummmm--I wouldn't exactly say he's "promising" to call. More like, he's making vague statements that would lead you to believe you might hear from him soon. But remember, when they're in the tunnel, 2 years can seem pretty "soon" to them, because they've lost all sense of time. Also, although when he wrote the email he might feel determined to keep in touch regularly, he could easily swing to feelings that he's got to avoid you because you're too controlling (just a random example), because the MLCer really does cycle from one position to another. (And the closer they are to being "done," the faster they cycle.)
As your thread title says, he's confused. And he's going to be that way for a long time. Even if he has moments of clarity when he thinks he knows he wants you, there are other times when he's just as sure he couldn't bear to lose Helen, and times when he just wants to run from everything. Lots of MLCers come back too soon, and end up leaving again. Unless you feel you could cope with that, don't pay too much attention to anything he says/does right now. When he comes to you and can look you in the eye with smiling, non-alien eyes and you sense a feeling of peace and confidence in him you haven't seen through all this--then you know the confusion is over.
My advice would be, do reply, but wait till you've collected yourself enough that it's not a big deal to you. Yes, keep it light and funny. And then go back to all those amazing GAL activities you've got lined up and really enjoy them. Because it's only after we genuinely believe that we can have a great life without our H's/BF's (or anyone else) to "complete" us that we're ready to enter into a genuine, healthy relationship.
