I have a brother born in Australia?

he would be about 10 years older than me. My fathers1st wife committed suicide at the the age of 17 or 18. I want to find my brother. Can anyone help me with finding him please. As far as I Know my dad gave his son up to his Mother and Father in Law. Dad is 73 now. I do not want to bring his past up. He is an old man. My brothers name is Kevin Miller or Kevin Townsend. His mothers name was Dianne. Can you help please/