I'm no expert in this. We prolonged weaning for way more than I'd ever tought. But this is how we did it, it may be helpul because like your ds, dd slept with 3-4 every night.
I bought a pack of pacis and told her that those were the last ones we are buying. Once she brakes them or loses them, that's it, no more pacis. Each time we needed to throw one away I'd tell her ok, now you have x more left, when they are done we are not buying any more. I think repeating this helped a lot. She tore some, lost some, some fell off the bed and we couldnt find. The last one fell off in the middle of the night and we couldnt find it, we told her we'll look in the morning, she went back to sleep and in the morning we told her it was gone and there are no more pacis.
We were quite surrprised that it worked ( we've talked about it a lot, I've taken them away but gave them back because she was upset, we put them in an envelope to send to santa, but those methods didnt wprk) but when bt came that day she needed extra cuddles but went to sleep without any problems.
Hope that helps.