Whether you should email depends on your intention. If at some point you would like to start dating again or you want the friendship then go ahead and continue this relationship. There is nothing wrong with emailing and you seemed to make a very insightful choice concerning his situation. If you think that things won't change or there is no benefit to doing this then I would let it go. The difference is really dependent on your intention. Don't feel obligated to reply back. If you think nothing will change, then don't bother. Your time is valuable and you shouldn't pursue a relationship that is going nowhere. I would send him a nice email saying that you want to move on and he should too. If the relationship was going somewhere it probably would have already. May be an example of okay guy, wrong timing.
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