I think I would try to contact the following website links to see if your parent can submit a copy of your grandfathers death certificate to see if they would give your parent (your grandfathers child)the birth certificate. I would think it would have more impact if it came from your parent as his child, not from a grandchild.

http://www.geocities.com/CapitolHill/9606/states/alabama.htm


A place you might post for help would be:

http://www.gsadoptionregistry.com/

This is G'S Adoption Registry - Free/No Fee
There are "Search Angels" for different states located here, a message board, a form letter to obtain your non-id information from your adoption records and much more.
The "Search Angels" at this site have a high rate of success due to their access to records and databases.
Their databases may pick up his birth and adoption in Montgomery County Alabama.

Good Luck,
jodad1911