LADIES I NEED ADVICE ASAP!!!!

My friend had to bring her baby in today cause he stopped breathing and he lost consciousness. They said it was pneumonia so they gave him meds and sent them on their way. They are now in emerg again because he won't keep anything down .. Not even his medicine.. Please . What could this be ? 
Edit, he's 7 months 
And please no negative comments like one lady on here... I'm worried and scared and sympathizing with my friend.. Not looking for a bitchy womans advice with verbal diarrhea.