New at this and could use some help!

Hi there! I have recently started trying to track down my boyfriend's birth father. BF was born 3/3/1985 in Athens, Texas. When he was six or seven, he was adopted by his stepfather and issued a new birth certificate with the stepfather's info. We basically know nothing about his bio father beyond a name. BF thinks he was listed on his original birth certificate, and having that info would be handy, but is it possible to obtain a copy of the original? Bf's mom passed away nearly eight years ago, so we don't really have much as far as info sources go. Thank you in advance for any assistance!