mikeHerberich on Family Tree Circles

I need to prove my father was indeed American by showing he spent at least 10 years in the US after the age of 14, in order to become naturalized as a US citizen, the US Embassy in Bern, Switzerland says. I live in Basel Switzerland, born here 03/25/1950 to my father and my Swiss mother Rosemarie Herberich during my father's stay in Germany under the US Army (bookeeper acountant (auditing)).
Apart from that I am interested in genealogy of both my lines, Murphy and Herberich. Any hints are greatly appreciated.
My father was married to Isabel Frances Chapman in the US and had a son there, Paul Eugene, born 01/23/1942: a half-brother of mine!
Paul had 6 children from 3 wives: Carrie, Maureen, Eileen, Raygen, Collen and Erin. I'd like to contact them (e-mail), mainly for confirmation/ information pertaining to the above goal of obtaining proof.
Thank you for your every hint.