Hi I'm 28 and found out my brother was adopted how can I find him he is my faters child and I don't think my fathers details where on his birth certificate please HELP!!

He may not even know he is adopted.

The ONLY thing you can do is to try to locate him through reunion websites, and even then I would discourage it. I think that initial searches really should be initiated by the adoptee or the birthparent, as they are the ones whose lives are most affected.