First of all, you shouldn’t expect baby to sleep through the night until after four months or so. Since it can take awhile for baby to settle into a routine, you may want to temporarily move your older child out of the room.
Make sure you make the move fun for your older son. For example, make up a special bed in your room (using his mattress), let him decide where to put it in the room, and thank him for helping to teach his brother how to be a good sleeper. You can give him a special treat like stickers or a new pair of pajamas. You may also want to purchase or borrow a white noise machine for your older child’s new sleeping space. This will help him sleep through any crying or noises you and your husband may make during the night. Tell him that he may hear his little brother crying in the night but that he’s okay and you’re making sure he’s safe.
Even though true sleep training usually can’t be started until baby is at least four months old, our advice in the meantime is consistency, consistency, consistency. Before you start any sleep teaching program, however, make sure your son 1) is healthy, 2) hasn’t received shots within the past 48 hours, and 3) isn’t experiencing a major life transition (e.g., mom going back to work). Pick a regular bedtime, incorporate a calming bedtime routine, and follow our tips for creating a sleep sanctuary.
When it comes to the best sleep teaching approach to use, it’s really a personal decision. You’ll have the most success if you pick one you and your partner can BOTH commit to and stick with.