ITA with what Katherine says ^^^^
My instinct here is for you to stay in his room with him for a few nights and then GW from there. Sitting outside shushing him might be better, but, frankly, you'll be more comfortable and stand a chance of being rested if you're lying down on the floor. I would not want to be sitting on the stairs in the middle of the night. Maybe you have the option of camping in the hallway? I would make sure not to be in the same bed (somehow I think you were when you did it before, but I might be wrong). I would preface the whole thing with a 'big chat' a few times during the day to lay down the law - no talking, no messing, I will be there for you but you must do your bit, your water is here, your dummy is there, whatever. His behaviour really sounds like he needs reassurance, and I wonder if there's any read across into the daytime. Sometimes doing things a bit differently in the day can make a big difference.
My LO2 can get into an incredibly frustrating loop of BT nonsense so I generally just don't engage with the substance, in the nicest way possible, it is better for me keeping my cool, otherwise I just start arguing back and we all know who wins arguments with 3 yos (the 3 yos!). I just repeat whatever sleepy phrase ('it's the middle of the night', 'it's time to sleep') and keep interaction minimal.
I'm sad that mean old nurse is out there dishing out such harsh advice. My LO1 had his dummy til well past 3.5 yo!
hugs Jo hope you can recharge your batteries somehow.