I can see why you folks are asking for location! There are 37 Saint Marys Cemeteries in Massachusetts!
http://www.findagrave.com/cgi-bin/fg.cgi?page=csr&CScn=S...Saint Marys Cemetery, Norfolk County, MA:
Town # graves as of 2 Jan '15
Franklin 888
Canton 2,317
Randolph 1,293
Quincy 912
Needham 1,151
Foxboro 2,145
Saint Marys Cemetery, Suffolk County, MA:
Town # graves as of 2 Jan '15
West Roxbury, 177
Dorchester, 192
From your tree, these are some of the Weschrob mentioned in your post:
1920 census 279 Colburn Street, Dedham, Norfolk, MA
WESCHROB, Amieal head 56 widower, painter
--Amieal F son 26
--Richard E son 24*
--Charles A son 22
--William J son 15
--Anna E dau 12
--Sarah L dau 9
(*his son Richard E Jr bur. in MA Nat. Cem., Bourne)
My suggestion is: Call the cemetery, I realize the Catholic cemeteries do not always give out information, but try anyway! --then, if you are absolutely certain that he is in one of these cemeteries, post your information -birth, date & location, death, date & location and add your picture of the headstone if you have one.
You state he has a military headstone, have you checked your military resources on Ancestry? was there a headstone issued?
Please note: I am not related, just trying to clarify and help out.