He doesn't know where to use commas and how to make his sentences flow. Too many of them are unnecessarily run-ons. (Long sentences are sometimes exactly what y

He doesn't know where to use commas and how to make his sentences flow. Too many of them are unnecessarily run-ons. (Long sentences are sometimes exactly what you want, but there's an art to it.) He has some fragments and, while sentence fragments are sometimes great, he doesn't have the subtlety to use them properly. (Most people don't; in that case, stick to full sentences.) He screws up on punctuation all over the place and uses abbreviations like "am" for "morning". This is fine if you're texting, but he's not. There's a general lack of clarity and professionalism in his writing. He doesn't respect others in the conversation enough to give them his full attention. Get him to talk about himself, and he'll go on and on and run over any obstacle (proper grammar, good taste) but expect him to express a thought clearly and it won't happen.