My autistic son covers his ears when he gets overstimulated. how can i help him cope better?

Systematic Desensiti: Systematic desensitization. From an early age start to expose him to sounds in playful situations. Bring him closer to the offending sounds gradually (from a distance, from a closed door to the same room etc.) also reward him and reassure him for tolerating target sounds. Try to avoid any of the headphones, calming music, or other techniques that will increase his isolation from the real world.