This is such a common milestone and honestly so many of us have been through this exact thing, so you are definitely not alone. What worked for my girl was doing it very gradually, first just moving the cot a little further from our bed over a few nights so she got used to the distance, then eventually transitioning her to her own room. You can also try staying with him until he falls asleep in his room, then slowly shortening that time each night so he learns to settle on his own. Just be patient with yourself too, some nights will be harder than others but consistency really is the key.