Thanks for your great question and you are not alone. It happens in about 5% to 25% of great sleepers. They suddenly change somewhere around age 2 to 3. The introduction of a new sibling can be the cause and sometimes it is simply – age.
A great place to start is bedtime. Take a look at when he is going to bed. If you are tucking him close to 8pm, I would encourage an earlier bedtime as that can encourage a second wind. It can happen at bedtime – harder time falling asleep or through the night with multiple night wakings and/or an early wake up.
Next, take a look at screen time. TV and computer devices appear to be relaxing but they over stimulate the central nervous system and cause night wakings, nightmares and night terrors. Try making sure there is no screen time after 6pm.
If he is napping by day, it might be time to eliminate the nap as daytime sleep can start to interfere with night time sleep sometime between age 2 and age 4.
That is great that he is not fighting going to sleep! Congrats. It is also important that if you are waiting for him to fall asleep, then he will need you to fall back asleep in the night. If you are waiting at bedtime to even a drowsy state, then, this is your first step. You need to be able to leave when he is wide awake.
If it is simply night wakings, then I would suggest sitting down with him and explaining your expectations of him sleeping through the night again and using a sticker chart and a reward strategy. You will also need a clear consequence in the middle of the night too if he chooses to come and find one of you and ask you to stay with him until he falls asleep. (This is one of the reasons people hire me – is to help them with a gentle and effective solution). I would also suggest that you give him something of yours to cuddle with in the night like a t-shirt over his stuffed animal as he is going to miss you or your husband’s presence. Another very useful tool is a Toddler Clock (see my tips here), or even just an inexpensive digital clock. Tape over the last two digits and when you explain that he needs to stay in his bed sleeping, show him the clock and tell him which number he needs to look for – be it 6 or 7. Make a poster too with the number and post it in his room as a reminder. Then when you go to him in in the night, it is a gentle, “Son, it is not … morning 7 yet, you need to go back to sleep.” With time and practice, hopefully his body and brain lets go and he starts sleeping through the night again and the clock and poster are no longer necessary.
You can also try using a Bedtime Pass.
I hope these free tips are enough to solve your current sleep challenges. If not, I do offer a FREE 15 minute telephone consultation. That’s the best way to see if I am the right fit for you and your family.