I want to know you

I wish I could find my half brothers. They are called Richard, and Damian. They may have my dad's last name which is Phillips. His first name is Derek. However, they havn't seen my dad at all. My dad split up from their mom when they were very young, and she got full custody of the children. The mothers name is Janet. Now they both must be in their late 20's, early 30s. I don't even know where to start, I really want them to know that they have two half siblings. Its me and my brother. Another reason is that my dad is terminally ill and if they dont meet him then they will never get the chance. Yes, there is a possibility that they wouldn't want anything to do with me, my brother and my dad, but I want to try. I would like to know my family even though they are only half brothers :'(