The New York law, regulations and other guidance seem to be written by someone practicing English as a second language, but I will go out on a limb here and say that what they mean is that it qualifies as long as the decedent would have met all the other conditions, but not NY residency.  Otherwise they would be saying that someone who worked in NY for 40 years, then moved to Alabama three months before death, would lose the privilege of passing on his wealth to his beneficiaries.  

Is your client the only beneficiary?  Because there are some rules about the $20,000 being divided among all of them.