Does he take lots of solids? You could definitely try doing a night feed at 5.30 and see if he will settle back to sleep. Another thing to mention is that, for us, EWs were always OT. The only things that worked for us were to do an early bedtime, and, if that didn't work, also push the first A time of the day. Around this age we went to fixed nap times: it doesn't work for everyone but it's worth considering - I chose nap times based on a 7am start, and would just stick to those timings no matter what time he actually woke up. There were a few days of OT, but he adapted pretty quick. Like I said, it's not for everyone but just thought I'd throw it out there.