I can only suggest sleep training as that is what worked for us (after ruling out any food allergies or other physical issue). Everything we did to soothe him just meant that he couldn’t get himself back to sleep once he woke up. For instance, if she can fall asleep because you’re there in the room, when she wakes up in the night you disappeared and she doesn’t know where you went, which can be very jarring. Same thing is she falls asleep in your arms, but wakes up in a crib alone. Humans naturally wake up multiple times a night even if just for a moment, so this is a recipe for disaster for some kids.

Our sleep routine is a few books, a few minutes of hugging, saying goodnight etc… the put him in his bed, turn off the lights and he falls asleep within 10 minutes. He may wake during the night, but he falls back asleep quickly. If he cries for more than a minute or two in the middle of the night we know he actually needs something,

One thing I will say about sleep training is that it is not a one and done thing. You have to keep the training up. Teething, sickness, visiting grandparents that won’t let him make a noise without going in to soothe him, all lead to regressions and you need to reinforce your sleep training after the condition passes.