John S Grey
Birth unknown
Death 13 Feb 1929
Burial Holy Cross Cemetery
Brooklyn, Kings County (Brooklyn), New York, USA
Plot Diamond Square, System: CEM, Section: DIAM, Row: C, Plot: 130
note at findagrave: Gravesite Details Death date is interment date.
https://www.findagrave.com/memorial/172941349Fanny Grey
Birth unknown
Death 11 Sep 1953
Burial Holy Cross Cemetery
Brooklyn, Kings County (Brooklyn), New York, USA
Plot Diamond Square, System: CEM, Section: DIAM, Row: C, Plot: 130
note at findagrave: Gravesite Details Death date is interment date.
https://www.findagrave.com/memorial/172941343/fanny-grey-------
Holy Cross is a Catholic Cemetery, if that helps rule them out or keeps them in as relatives.
So you have an approx. death date for both, but I don't know how available the NY Death records are. Rules vary from state to state. Their death records should have a space for parents' names. Whether they will be filled in correctly is anyone's guess.
-------
John S Grey is elusive before 1900. The best bet for tying them to Sunderland might be the birth record for their son John G who sometimes says he was born in England, sometimes in the US.