My father passed away on March 26, 2007. He lived In The Philippines. All his mail & CC info was being sent to my house in Illinois. On the morning of his death, I,his son purchased a plane ticket to the Philippines using his credit card that was sent to my house. The CC company does/did not know that he did not live here. Since he was the only authorized user with no co-applicant, who would be responsible for the plane ticket?

Well morally you are. But if you don't want to pay it don't. The stupid bank will make it up on all the "rip offs" they use to steal from everyone else.