I also have a 4 month old boy and his sleeping patterns are very similar - fortunately 2/3 times a night rather than 6 times! He used to wake a lot more when we were cosleeping but since moving him out to his own cot in his own room a few weeks ago he has improved (I know some people would not think 2/3 wakings a night is an improvement but he is exclusively breastfed as he refuses to take a bottle so I feel we have come a long way compared to a month ago). He does not go down until 9/9.30 pm and if we are lucky will sometimes sleep until 2.30/3.00 am but most nights he will wake up around midnight for a feed, again at 3/4am and and again around 6/7am. He does go back to sleep straight after a feed but I would love to cut it down to 2 feeds rather than 3, I really think he doesn't need the midnight feed and like your boy doesn't always feed for very long, he is just used to being fed back to sleep. I know I probably need to let him cry a bit before running to feed him every time he wakes up, worked with my 20 month old when he was a similar age but he was taking full bottles by then so I knew he wasn't hungry, with this one I never know if he is genuinely hungry. He also is not hungry when he wakes up so he does not need all those nighttime feeds. We don't really have a routine during the day, I still feed him as and when, usually when toddler is not demanding my attention. My little one also has a constantly blocked nose and teething has started as well, had his first dose of calpol at the weekend and that knocked him out for 6 hours! So no real advice but just to let you know we are in a similar situation, I think we probably need to be a bit tougher before we see a real improvement, just need to be in the right frame of mind to do that. However I thought it would be really difficult to get him out of our bed and in the end he didn't complain too much so I know trying to cut out the midnight feed is the next step.