I have never heard that babies all of a sudden wake up in the night when they start walking...? First of all, he should be going to bed earlier. Little ones need their sleep! Also - get him on a routine during the day and make sure he is eating meals...that way he won't need to wake up at night. Also - he really shouldn't be sleeping in your room at that age...you should have a bedroom for you and your husband! When the new baby comes, she will be in there as well, and that is definitely not a habit you want to start - two kids in there with you at all times! And especially if the NB wakes the 1 year old! My 14 week old baby sleeps more than your son - and I'm sure he needs his rest if he is going to have energy to walk with! If I were you, I would put him in his own room, ignore him when he wakes up if he is just making noises...if he starts crying, then just go in there after 5 minutes, console him, then put him right back to bed....then the next time wait 10 minutes, then 15, and so on....he will get the picture. It's night time, not snack time, play time, or any other time.