Her burial was in the Forest Park Cemetery:http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=wi...
Clicking on the name of the cemetery will take you to their contact information. Contact them to see what records they may have, such as a burial permit, death certificate, possibly the obit. The permit or DC might have the name of the funeral home. Funeral homes usually help write or write the obit from family information and see to it being publicized in a local paper. An obit sometimes is not written based on the cost, decisions of family members, length of time living in an area, etc.
Clicking on: http://www.cclerk.hctx.net/applications/websearch/RP.aspx
gives you a database search, entering "Wilson Shirley D" as Grantor will give you 4 documents. The last is a document concerning her estate. The Grantee was Kenneth E. Wilson, probably her son. Sometimes these estate documents contain the death certificate.
on the right side is "Probate Court." Clicking on it is a Search Databases. Enter "Wilson Shirley D." The last entry is Shirley Diane Wilson, filed by Leon George Busby, a brother? There would be a copy of the will, if there was one. If no will (Intestate), the court would decide on distribution of the estate.