If he isn't awake when he is crying it could be night terrors all of my kids have had them at one point in thier childhood, don't let the name scare you, really they are nothing more then a child waking up crying for no reason at night and still being asleep, each one of my kids had to be handeled differently, the younger they were I found just soothing thier backs w/out picking them up was best, they have no recollection of them in the morning, it is a phase and will go away on thier own, each of mine kids lasted for different time frames from a couple of weeks to 6 months, the older they were the less involvement I had cause it just seemed to make it worse, my know 15 year old boy had them the longest and the only way to get him to stop was to go in his room and tell him to knock it off and go to sleep, but in the morning he would have no memory of it, my 16 year old got them at about the same age as your daughter and I found that if I just left her alone, no touching, or talking to that w/in 20 minutes or so she would be back asleep, and with my know 6 year old I would have to just go in and gently rub his back, and making a shushing type noise, actually it's a native american sound it was more of an ah ah sound and that would soothe him back to sleep in about 5 minutes,
Don't forget that sometimes it takes baby a while to get back into a sleeping pattern after teething or colds,it's like starting all over again, also turn your monitor down, so that you aren't hearing so much of the sounds he's making, have your husband go in the room and "cry" at a level that isn't to loud and keep it at that setting so that anything above a loud moan is all you hear. I don't know if I was any help but good luck, I know the feeling of no sleep and it sucks.