Can you switch it to a pacifier?
We recently got similar feedback and switching to a pacifier has been a life saver
I wouldn’t switch to a pacifier because you’re just going to have to wean them off that eventually. We’re working on weaning the overnight bottle and I’m just incorporating rocking and singing to soothe him instead. It will take a few night if not more to get in the routine but I would try that first!
Babies can develop ear infections pretty easily when they fall asleep drinking milk. I would try changing up his sleep cues so he learns new ways to feel soothed as he’s falling asleep. Remember that takes repetition and consistency are key when it comes to sleep cues. Hope this helps!