Your best bet for death certificates are from Ky State Vital Records. I do not have their address handy right now but it is easy to lookup. If you do not know the year of their deaths, I think that Carter County does have some cemetries online if Carter County is where they died. Grayson is the county seat and Olive Hill is just up the road from Grayson. You might be able to get the certificates by knowing the birthdates, I have never tried that but it might work. Certificates are very helpful but they are also considered documentation so I am slowly trying to get as many birh/death ones that I can. Also you might try military records. Do you know if Willie served in the military at any time. The records do not give the names of parents usually, they do give a lot of personal info, includng wives and children. If there is any way that I can help, let me know. I have quite a lot of info on the Everman and Kibbey families since they are my direct ancestors, if you find a connection to them.