Answer:
They died due to suffocation.
Explanation:
The whole Lannister’s family died due to the shortage of oxygen in the room because of squirrel’s nest in the chimney. Chimney is the only way for the removal of toxic gases and smoke produced from the burning of wood. The squirrel’s nest block the passage and the smoke and toxic gases stay in the house which causes suffocation and the whole Lannister’s family died.
