K.G.
Jilly,
We recently went through a number of night wakings with our 2.5 y/o daughter. It seems that my rocking her before bed, not to sleep, had thrown her off to where she wanted rocking when she woke up at night. I don't know how we got to that point so quickly, since it was maybe a week of 5 mins of rocking before bed. Apparently she was hooked though. It may be that the soothing when he was sick is something that he's wanting now.
We broke the cycle by sending my husband in to check on her in the night, since she wants mommy and also not rocking before bed. Good luck.
K.