Some of the more intense stuff like controlled crying isn't recommended until 6 months. They will go through phases anyway when start waking, persistence will usually get you through. I'd suggest limiting as much as possible the things that they become attached to in order to get back to sleep that will make it harder to break the habit of waking and needing re-settling, such as bf and a visit to your bed. If he puts himself to sleep during the day and firstly at night, then it sounds like just a phase and will probably grow out of it.