Im afraid no one would know the outcome if he does that but there is a good chance the app will be refused because as others said he has to be in Canada to be able to sponsor you its also stated clearly in the links above.He could try and explain ?
Good luck
I'm sorry to be the voice of doom here but I DO know the outcome. He WILL be refused.
Fact 1 - He moved to the US in 2005 and applied to sponsor his parents in 2006. He LIED to CIC when he applied to sponsor because he would have stated that he was living IN Canada on the sponsorship application.
Fact 2 - He has not returned to live in Canada and is still living in the US.
Fact 3 - He is not eligible to sponsor.
What can he "explain" to CIC? How do you think CIC is going to like it when they see that they have been lied to for the past 5 years? Even if he returned to Canada now I would bet dollars to doughnuts that he would still be refused because he didn't meet the eligibility requirements in the first place!
Perhaps you can apply on your own merits as a federal skilled worker and then later sponsor your parents. I don't know what else to tell you because you keep looking for a way out of this situation when there isn't one. I know you don't like what I'm telling you but I refuse to lie to you or give you false hope.