How to avoid a person. Thnq in advance.

My cousin and I were of same age and buddies till our intermediate. I like him very much. Now he is very much changed, became very arrogant. Not talking properly. Ignoring me in a bad way. Exploiting situation n creating bad impression on me. He is master in gaining others sympathy. Everyone in my family listens to him. He is also controlling my brother's children to not talk with me. He don't like when I talk r spend time with them. His family is rich. He is like head of our family n helped my family in bad times. I waited for long time n tried to talk, but no use. If I tell this issue with anyone, nobody will care because they are rich. I am very disturbed n heart broken. How to avoid him, please suggest... Thnq in advance.