It sounds like your DS could benefit from working with a writing coach or tutor who specializes in helping students with learning differences. They can teach strategies to break down the writing process and organize thoughts effectively. Executive function coaching might also be helpful, as it focuses on planning, organization, and task initiation, which seem like potential areas of challenge for him. Additionally, exploring software tools like mind mapping apps could help him visualize and organize his ideas before writing. Encouragement to use talk-to-text could also complement these strategies for overcoming initial writing barriers.