How do you handle a child who refuses a subject entirely?

Separate the skill from the activity. Can he narrate orally? Record him and transcribe it yourself. He has the cognitive skill without the physical resistance.

Find the real reason. Writing refusal is usually motor difficulty, perfectionism, or disconnected content.

Back off entirely for one term. Do not mention writing. Voluntary writing often appears in unexpected forms: notes, lists, game instructions.

Typing as writing. Some children have a physical aversion to handwriting with nothing to do with the cognitive act of composition. A keyboard changes everything.