I laughed reading this because I did exactly that with our DS6 and book reports last year.
He was too slow to write so he dictated to me what the story was about and I wrote it down and he later copied it.
I told the teacher this is the only way he will do it. That he won't sit there and write it out.
She said well at least it is his own words and that she can tell when a parent writes it.
So No I do not think it is cheating if the words are hers