And here we have his respiratory system~

His lungs have 3 lobes compared to the usual two humans have (upper and lower if I recall correctly).

The circular lobe on the top of the lung near the rear of the lung allows him to "breathe" electricity, like Spyro for instance. It builds up a huge static charge to do this.
The bigger, longer lobe running from the rear of the lung, along the bottom, towards the front allows him to breathe fire. Methane gas is produced in this lobe as a catalyst. There is a bony valve between this lobe and the rest of the lung with two parts. These click together once to make a spark and boom: fire.
His trachea is coated in thick mucous to protect the tissue from the high temperatures of his breath attacks.