Louisiana Death information is considered private for 50 years. Death information greater than 50 years old is available from a few resources:
1) ONLINE: family search pilot:
http://tinyurl.com/yjwcmu4
(Wait for the page to complete.) Although these records are a work in progress, info for Betty is listed.

2) The Louisiana State Archives (Deaths before abt 1958). Read the information on ordering Vital records.
http://tinyurl.com/ykrpbs8
-- OR --

Search their database.
http://tinyurl.com/489gzq
Select "Advanced Search" and enter the surname and parish (optional). This search also returns the ordering information (page/volume/year and parish)and a link to order online.

You can order a copy of a death record online and it will be mailed.
You can also order by sending a request via the U.S. Postal Service, using the online form.