S.R.
I had the same difficulty with my son. We would feed him a bit more right before we put him to put. Also we started putting him to bed earlier. That stopped him waking at around 1am but he still was waking between 4-5 I would go and give him a quick feed and he'd go back to sleep. We use a humidifier also but he still wakes sometimes.
Also he started teething at that point. Just try to comfort as best you can. We did a little cry it out waiting for about 15 min before we'd go in, this helped with some of the 4 am wakeings. Good luck.