What Causes Facial Twitching, Disorientation And Mood Swings?

my son had a sepsis infection and took antibiotic intravenously for several weeks. While lying in bed, he his saliva went up his nostrils, and he believes that is what caused his face twitching, disorientation, physical immobility and mood swings. I took him to the ER they did MRI and CT scan and find nothing. His symptoms are getting worse.