What Does 3.6 Potassium And 137 Sodium With Fever Mean?

My brother was fall down from roof. Only multiple Blood Cloting and swaling in the back side of the head other parts are normal. last 21 days he is in NICU and the treated by one Neuro Surgen. Last day he suffering with fever. presently his potasium is 3.6 and Sodium is 137. Can its right that a neuro surgen treated this patent and also confirm that how much time is required in the NICU.