I want to find my paternal grandparents.

My name is Kristen Peters and my father, Matthew Wayne Findley, was born May 20, 1964. The only information that he has about his birth parents are that they're last name is Phillips. Every time he asked his adoptive parents about them they became irritated and told him not to worry about it because they were the ones who raised him so it shouldn't matter. I would really love to find them for him so he can have some closure to his questions about why he was placed for adoption and if he has any brothers or sisters. He had a doll when he was little that he took everywhere named Jimmy that my adoptive grandparents gave to him upon adopting him when he was 3, now I don't know about you, but what 3 year old randomly comes up with the name Jimmy when no one around him is named that? This lead my father to believe that he may either have a younger or older sibling named James or Jim. I'd also like to meet them myself because the only 2 paternal blood relatives I have are my father and my brother. If you have ANY information regarding them please comment or PM me. I'd greatly appreciate it.