2nd Grade Writing

I am using Writing With Ease with my second grader and we are on Weeks 29-35 where Day one is copywork, day two is narration exercise, day three is copywork and day four is narration exercise and copywork (where I write down his narration and then he copies it).  My question is when he is narrating the passage do I write down EXACTLY what he says or do I correct him to make it sound right?  for example he narrated from the passage about the grasshoppers from On the Banks of Plum Creek and he said “Laura thought she saw a stormcloud but then it looked like snowflakes.  They were large and very thin.”

I don’t know if I should just leave it or if I should write it so it sounds correct?    Thanks!