This is considered a ‘cry’ method of sleep training. This technique entails allowing your baby to cry while checking on him at intervals. The goal here is to reassure him every so often that you are nearby and to reassure yourself that he is okay. When you go to check on your baby, you are not “supposed” to pick him up nor engage him much, but simply reassure him using your voice and a loving pat for 2-3 minutes, tops (watch the clock!). With this sleep training method, the goal is NOT to help baby fall asleep – that is what he is learning to do on his own! Instead, the idea is that he falls asleep on his own, in the same “environment” in which he will awaken periodically throughout the night. The knowledge of how to fall asleep unassisted at bedtime will pave the way for him/her to go BACK to sleep throughout the night. Over time, you gradually increase the amount of time between your ‘checks’. See a more detailed step-by-step explanation of this method here: The Ferber Method
Thank you for checking out The Baby Sleep Site! I’m sorry to hear you’re having so much trouble with sleep. Based on your comment, it does sound like your little one might be coming into the 4 month sleep regression. We have an article with a lot of information on that here: https://www.babysleepsite.com/baby-sleep-patterns/4-month-sleep-regression/
One common misconception about sleep training babies (also called sleep coaching) is that there’s only one way to do it. But this could not be further from the truth! In reality, there are a number of ways many parents can work to help their babies develop healthy sleep habits and stop waking up in the middle of the night or taking short naps. Some methods involve crying, but others involve little to no tears and are very gentle.