Dreams involving significant others, especially those who are going through difficult times, can often reflect our deep concerns and emotions regarding their situation. In your dream, standing in a desert symbolizes feelings of isolation, emptiness, or a lack of direction, which may mirror your feelings about your friend's current state. The desert can also represent a harsh environment where survival seems challenging, akin to what you perceive your friend is experiencing in real life.

Your friend’s refusal to come home may indicate your feelings of helplessness and frustration in trying to support him. His belief that he belongs with the devil could symbolize a struggle with guilt, shame, or self-worth issues. This part of the dream suggests that you may be processing your friend's internal battle and the pain he feels about his past actions.

The transformation into dust at the end of the dream can symbolize loss, finality, and the fragility of life. It may be a manifestation of your fears about his safety and the potential outcomes of his current mental state. The news of his death in the dream could reflect your anxiety about the situation and the worst-case scenarios that occupy your mind.

In interpreting this dream, consider it as a projection of your worries and emotions rather than a literal prediction. It may be helpful to talk openly about your feelings regarding your friend's situation, whether through support groups or friends who understand your concern. Additionally, this dream could be a prompt for you to encourage professional help for him, as it highlights the importance of care and support during difficult times.