As Jeremy is really suffering from the treatment, he has been having a lot of attention overnight (obs for the last 2 nights have been hourly, sometimes even half-hourly).
Jeremy has been having pretty high fevers >40 degrees more frequently than before - the concern is for the time just after the fever has peaked - there may be dilation of the blood vessels (leading to a drop in blood pressure). When this is combined with sleeping (which naturally drops your bp), Jeremy's bp drops to the level where the nurse is concerned, and calls for a doctor to check on him. For the past 2 nights, they have given him a fluid bolus (basically ~200ml of saline delivered intravenously). This increased the volume of fluid inside the blood stream, and has managed to bring up his blood pressure. Thankfully, Jeremy's body responded appropriately each time, and no escalation was required.