Too often kids have trouble writing because they can't think of a place to start. Here's a simple prompt that's guaranteed to get him writing. Encourage him to pen a story about his favorite sport—not only is it a great way to boost his sentence-building and handwriting skills, but it's sure to keep him entertained in the process.
See the rest of the Story Starter series for more creative writing practice.
Which set of standards are you looking for?