my grandfather certificate of naturalization can be apply as my father's proof of cit

[kotaro]

hi to everyone ... and good day...

i am actually confused on how can i have my father's proof of citizenship?
My father acquired his U.S. citizenship through his U.S. citizen father who was a member of U.S. Army and served during World War I and II. I only have my grandfather's record of his military service and his copy of certificate of naturalization... My father never had a chance to go to U.S. cause he died but the consul approved all the application for citizenship of my father and his brother and sister... Actually we are the only family left here in the philippines all my aunt and uncle are living in U.S.
Now my question is can i just present my grandfather's certificate of naturalization as proof of citizenship for my father and his military records for my father proof of physical presence...? If not, to where can I possibly have and look for that records ... help pls...