He's definately homozygous double merle, which, yes, is a LW. The Heeler (both Red & Blue) is also known as the ACD Australian Cattle Dog and they carry a dilute gene, not the merling gene that say, the Aussie carries, not the harlequin gene that the Dane has, nor the dapple that the Dachsund carries, but they are red and blue (red dilute and black dilute). I don't know if it is the 'leopard' gene, or what exactly the dilute gene is called, but it is the DILUTE that is the killer. The Lethal White term deals solely with the fact that it is the HUMANS who kills these dogs, not the genetic defect. The Lethal White genetic defect in the paint horse is, however, very deadly. Two different things. We use the term LW to draw attention to the abhorent fact that to be white for these dogs is a death sentence.
If I had a choice between blind and deaf, I would choose blind. My blind pup sails through life and tested high for agility. My deafblind is much slower, more cautious, and not being able to hear is a real hindrance. Sight is third on a dog's list behind smell and hearing.
Here's the breed standard:
http://www.acdca.org/acd_breed_standards.html
He looks purebred to me. He absolutely has the characteristics. They are strong squarish, compact, muscled dogs with double coats.
To see the eyeball anomalies (and he looks like he's got microopthalmia with some PPMs or 3rd eyelid defect, which is quite common on the double dilute), visit the aussie eye defect page at:
http://www.ashgi.org/color/eyedefects.htm
He's got a LOT of ear color, which is excellent. The lack of pigment on the hairs of the inner ear (the third ear) creates deafness. Often deafness is accompanied by a white ear.
To understand the genetics involved (and again, in our case of the Aussie, it is the merle gene, replace merle with dilute to apply to any homozygous dog), please visit KimK's wonderful explanation at:
http://www.handicappedpets.com/Articles ... /index.htm
To my distress, I see the Cocker Spaniel is now being bred with the dilute gene. And yes, we are seeing double dilutes in that breed now.