Ugh...just reading this thread makes me shudder... For the first 3 months of Brandon's life, he screamed from 6:00 PM until midnight...EVERY night. Nothing would help...not the sling, not carrying him, not nursing him, not car rides, not dancing, not rocking, nothing. Well, nothing worked for long. Basically it was a trial and error....we found a list of things that worked some of the time and then just kept rotating them until he stopped crying...
Fast rocking side to side (almost swinging in your arms)
Holding him belly down in your arms and swinging
Going outside in chilly air (this worked a LOT)
Running water and standing next to the running water/faucet
SHHHHHHHHHING really close to the baby's ears....the sound is like a SHHH and ocean wave combined
Oh, and have the baby checked for reflux. Bran had reflux too, which was made worse by the colic. Basically, there was nothing we could do but grit our teeth and deal with it....one day it suddenly stops though. And it's a truly wonderful day...LOL!!
If your sister has a husband/partner, make sure to switch off....4+ hours of screaming can really get the best out of you. DH was gone for a week when Bran was in his colicky phase and it was horrible. Most of the time, Bran and I ended up falling asleep while I was sitting up in the bed supported by pillows, but we couldn't remember falling asleep... Switching off is definately a good thing. And remember, it will pass.... Usually between 8 and 12 weeks it just stops.
~Brandon Michael (11/23/03), Jocelyn Lily Nữ (2/4/07, adopted 5/28/07 from Vietnam), Amelia Rylie (1/14/09), & Ryland Josef William (9/7/05-9/7/05 @ 41 wks).