In fact, we don't say like that. "Проконтролировать" something or someone means "to watch/control how something/someone acts/works/makes/proceeds etc". So, when you wrote "проконтролируйте его" it sounds like we have to look after your text as if it were your son and you're afraid that something bad can happen to him if he's not under control. Or we need to control how you're writing your text. In Russian "контролировать" usually implies a process, not a static object. I know, comrade iCake didn't pay attention to this aspect before, so you do as you do.
I guess it would be more proper to say "Пожалуйста, проверьте его". Actually, we make so-called "разбор текста". You can use it as well: "Пожалуйста, разберите мой текст".