ok. Now I dont really know what I am talking about (only been a mum for 10 weeks..), but seems like your night and day routine could do with a swap around. How about trying to feed him every 2 1/2 hours in the day, so he can get more calories down him do he doesnt need to feed so often at night.
My DS is in a vague 2 1/2 - 3 hour routine in the daytime, which tends to switch to a 4 hour routine at night. Try waking him earlier so he can get more feeds in - 7.30 ish (if he normally feeds at this time) 9, 11.30, 2, then perhaps 4.30, 6.30, 8? that would be 7 feeds instead of 6 in the daytime. then a df at 10 or so. Can you increase the amount he takes at any of these feeds too?
Good luck! It is horrible to have broken nights, I hope it sorts itself out soon.