I'll try to be brief.
DS just turned 4. He's not an easy LO, is easily frustrated, very dependent, lacks a lot in self-sufficiency, and has a speech delay (before starting pre-school it was labeled as 'severe'. I feel his expressive speech has greatly improved, but I'm unsure of how much his receptive speech has improved).
For almost the past year he's been waking through the night, at least once or twice. Sometimes it's to go to the bathroom, sometimes he tries to get in bed with us, other times we don't know why he's up. Most times he gets up though, he's very loud, often whining or crying for help, to be tucked in, help with the light (which he CAN reach), etc. DH is great and gets up with him, and quickly gets him back to bed. We try not to indulge these night time visits, but if we encourage him to do something himself or put himself back to bed, he freaks out and gets louder.
Now we're a month or so away from having LO #3, who will sleep in our room for the first while, and I'm starting to panic about having DSs disturbances to deal with on top of being up with LO multiple times a night! I will be one unhappy mama if mama and LO are awoken by DS after just getting back to sleep, for example. Our plan so far is to get a nightlight for the hall, a nightlight for the bathroom, and keep our door shut (we currently have it open most nights). That way if we hear DS in the hall, we'll (ie. DH) have a moment to hop out of bed before he comes making noise into our room, and direct him back to bed. We've also been talking to him about how he has to be quiet when he gets out of bed and that when the baby's sleeping in there he cant make so much noise, etc. But I would of course ultimately love to either get DS sleeping through the night again, or make him nighttime wakings more self-sufficient.
How would you deal with this situation? How would you deal with DS?
And, for bonus points, who would you put together to share a room once LO moves out of our room: DS, who still wakes once or twice and makes a lot of noise; DD, who sleeps quietly and peacefully through the night; and LO, who obviously wont have a very established sleep routine/sleep through the night for a long while yet.