Obviously you've read some of the NY Dept of Health website so you probably know that this agency will provide copies of the death certificate only to immediate members of the family, or to the officially designated representative of the estate (executor, etc.) of the deceased person. If you do not know these individuals well enough to ask one of them for a copy, which would actually be the easiest way, you might want to check to see if an estate was ever filed for Ms. West in the Surrogate's Court in Westchester County. There is likely to be a copy of the death certificate in the file for such an estate. The Surrogate's Court will not provide a photocopy of that certificate, but since it is part of the file you may go there and read it. Probate files are a rich source of genealogical information.