Bacterial Meningitis

My mom is currently in the hospital with Strepococcus Pneumoniea Meningitis, she is usually a very healthy 46 year old, caucasion, woman.  She went in on Wednesday with a migrane (migraine), terrible ear infection, nausea, and was just staring, and breathing really heavy.  Spinal tap confirmed Menigitis (meningitis), and started IV Antibiotics right away.  On Thursday she made a remarkable turn around, was talking, and laughing, and mostly understanding alot of things that were going on.  She was a little bit slow on somethings, but we were told we were out of the woods, so to speak.  Unfortunetly, on Saturday of the same week, she headed south.  She could no longer speak, her arms were once again curling up, breathing sounded hard, and her headache came back, and she was in a vegteable state.  My question is, why?!  Why would she be fine one day and then back to day 1 the next?  Her tests say that she has made slight progress to the treatment, and there is nothing else they can do for her.  We sit and wait, for a miracle.  Anybody know any advice?