If he is still under 11-12 lbs, I would say he needs to do what he needs to do. They naturally start a schedule (NORMALLY) around 3 months. So another month or so. You should start to see some kind of patern. For instance if he is going to sleep around 9am or so, lay him down so that he can go to sleep on his own, That way he doesn't go past his point of no return and won't go to sleep.
But for the most part I think he is still going to do what ever he wants.