Hey, it's me AGAIN with a sleep question .
How many hours the first few nights, days did it take for CIO to work? God I'm hoping it's not hours

I was staunchly anti-CIO but my 2nd son (5.5 months, we will wait til 6m) CANNOT fall asleep independently and our whole family is truly suffering. We've tried everything. My 1st son was able to fall asleep on his own and was a dream sleeper- I nursed him to sleep for 15 months and it wasn't a problem. Not so with DS2! So I think we need to do the Ferber method.
He really escalates. We've let him Fuss It Out up to 15 mins and he gets absolutely hysterical. I am dreading CIO but I am desperate and we owe it to him to stop the sleep associations (either nursing or holding him).