I agree that some kids just are better sleepers than others. If he is eating enough during the day, he is probably just using nursing to comfort himself. I don't agree with crying it out myself, but you need to find something that works so you both get enough rest. I would see if you can find something other than nursing to soothe him, I don't know if he takes a pacifier? I know some people are trying to get their kids off of it at just a little older, but I know that was my way of getting my son back to sleep rather than feeding him - he was just not a good sleeper and always woke up - I just didn't feed him during the night once he was old enough to not need to nurse during the night any more. I know most argue against it but do you try just putting him down next to you and patting him to sleep instead of feeding him and putting him down? My younger son always woke and I could never get him to sleep through the night until he was older (3, actually) but I just let him sleep w/ me as it was the only way we would get any sleep, crying it out never worked with him either. I would also make sure he is not sleeping too much during the day so he is tired at night to improve the chances he'll sleep longer at night. I would also ask his doctor for advice as well, but don't let anyone make you feel guilty if the cry it out method doesn't work for you, I know some kids just never stop crying and thus is just doesn't work for everyone.
Good luck and this too will pass, I would just do whatever works - and that is something different for everyone. Take care!