One lung hits are tough. Deer can live on one lung. I shot a nice buck last year in Muzzleloading season that had an arrow inside the chest cavity and took out one lung. Deer was otherwise healthy. Not surprised by the lack of blood without a pass-through. 6" is a good amount of penetration on a deer that are only ~ 12" wide.
I bet the deer is found close to where you last saw the eyes in the thicket. I would stalk the bloodtrail and be vigilant to see if you can spot the deer ahead. There is a chance the deer is still alive and in the area. You may be able to get a 2nd shot. Good Luck!