Be very careful to not let him train you into bad habits. I almost got caught when my DS was a year and a half. One night he woke up and asked for a drink, so we went to get it and were up for an hour. The next night he tried again and I almost set a pattern. It took three more nights of sitting with him saying no to get him back to his usual (not great) sleep pattern.
It has only been the past year or so that he has been consistently sleeping though the night without getting up one and two times and he is eight. He still will run into our room in the middle of the night once or twice a week. I think it is very difficult for him to disengage his brain and sleep and then when he wakes up, he thinks it is time to get going. (I really should get a clock in his room.)
