13 mo not sleeping through night since April- help!

[pinkladyslipper]

Hi, we're seriously sleep deprived- please offer suggestions...
DC2 is 13.5 mo. Was a great sleeper until April, so 10 or so months old. Since that time he has not cut a tooth (has 8 already) and has been cruising and walking with us holding his hand but wont walk alone. Since this time he was woken so frequently, practically every night. We might go a night or two where he will sleep through til 5 am if he hasn't woken duirng night but this is rare. So 3 months or more of this.

His routine is quite similar every day.
Brief routine:
*He will nap for about an hour in the morning
*He might have a nap in the afternoon for an hour (like now) but not always
*Last meal approx 5-5.30 pm
*We settle him down from between 6.15-7pm with his milk depending of how tired he is.
*He is usually asleep by 7.30 at the latest. He can wake any time from an hour after this til 4 am. No set time when he wakes, only that he will wake at some stage.

We have put ourselves into a bad habit of taking him up from his cot to another room and he will sleep in his pushchair quite well, which I think he actually prefers (he shares a room with DC1 (2y) and if DC1 is woken there's no sleep at all.)

I try not to give him milk during this time at night. He is usually full of beans, laughing and giggling like it is the middle of the day and not 4am.

Any ideas what we can do to keep him asleep all night? I am back to work soon and really need this to stop.
I pray that once more teeth come and he walks unaided he will sleep but I've been waiting and waiting.......

[nextphase]

Sorry, not what you want to hear, but I think you've been spoilt by a good sleeper! DS1 didn't sleep through til 2.5, and still is up once a week or so at 4.
DS2 was a dream - but that means he usually is up for the day around 5.40.

Waking an hour after he has gone to sleep suggests over tired to me. That would fit with the increase in mobility.