Dear N.,
I have cared for infants specifically for the past 20+ years. All children have their own sleep needs, however with that in mind I would like to suggest something that I have not seen anyone else suggest to you as of yet.
Anywhere between the age of 6 months to a year of age. I notice that some infants in my care begin to take shorter naps during the day, signalling the time in development when they are ready to go longer between feedings. This doesn't always happen at any particular age since as I said earlier each child has their own sleep schedule, some children clearly need more rest than others. Whenever they are ready I guide them toward a longer single nap. I do this by gradually lengthening their morning nap over time, until they go down after their midday feeding. This helps them (usually) sleep longer (usually 1-2 hours). Of course you don't want them to sleep too long or they won't sleep through the night:)
I also want to point out that I have noticed that many (almost all) infants sleep habits change just before they do something developmentally such as crawling or pulling themselves up or even cutting a tooth. Some infants will sleep longer than normal, others begin to refuse sleep, or get nights/days mixed up. If this is the case the child usually reverts back to their "normal" sleep schedule.
As you work on the above mentioned I believe the night routine should run a little smoother. In the meanwhile just hang in and provide a routine for him. I would begin by waking him up at the same time each morning even if he was awake in the middle of the night. Also, if he is awake and content in his crib in the am but it is not the time you have set for him to "wake-up" leave him until the set time. Infants thrive when following a routine. If you offer one consistently he will develop a sleep schedule you can both count on!
As we know consistency is key. I know, "easier said than done".
As he is going through this phase you may need to enlist the help of others in the household so you can get the rest you need to take care of yourself because "When momma ain't happy, ain't no one happy!"
Of course, as you said, each child/family are different. Just take what advice you feel will work for your situation and leave all else behind.
Hope this helps!
Good Luck!
D.
Owner/Operator Love'n Learn childcare
www.lovenlearncc.com