How can I help yr8 child with English?

[ZetaPuppis]

Ds is more factual so does ok in science and maths but seems to be slipping in English.
This weekend, he has to write a letter as a character from the book they are studying in class.
What pointers can I give him?
What is the teacher looking for in assignment like this?
Would buying the cgp English study book help him get better marks?
The comments he gets is that he hasn’t written enough.

He is expected to demonstrate empathy and understanding about the character. For a child that is factual developing these ideas can be problematical. Get him to mind map everything he knows about this character and then build on this to plan the letter. Which book/character is it?

I am looking for similar help...DD is getting baselines at start of Y7 now and the 'creative' subjects are her Achilles heel. I have just been searching for resources to help with creative writing and there seem to be plenty. However for art I am at a complete loss...