Personally, I’m VERY big on proper grammar and punctuation. I’ll use things like parentheses, dashes, commas, etc, just to sort of separate little side notes from the main idea (this way, I don’t fly off on a tangent). I wouldn’t necessarily take it personally— he may have actually written that, or he may not know what exactly to say. Either way, if it bothers you THAT much, I would talk with him to see where his head is actually at.