Interestingly, God's remedy for Elijah's depression was not a refresher course in theology but food and sleep... Before God spoke to him at all, Elijah was fed twice and given a good chance to sleep. Only then, and very gently, did God confront him with his error. This is always God's way. Having made us as human beings, He respects our humanness and treats us with integrity. That is, He treats us true to the truth of who we are. It is human beings and not God who have made spirituality impractical.
The question the doubter does not ask is whether faith was really useless or simply not used. What would you think of a boy who gave up learning to ride a bicycle, complaining that he hurt himself because his bicycle stopped moving so he had no choice but to fall off? If he wanted to sit comfortably while remaining stationary, he should not have chosen a bicycle but a chair. Similarly faith must be put to use, or it will become useless.