Contacting brother

I have a brother who was given up for adoption and my mother requested his adoption records. She had to sign a contact veto. Anyway I coundln't wait to get in touch with him so I called his house and we hit it off wonderful. He didn't even know he had a sister! He invited me to his house and we spent the evening together. Well my mom sent a letter by me to give to him. Everything was wonderful when I left that evening but he hadn't read moms letter yet. I called him a few days later and he said he didn't take the letter very well and he needed time to think. I am so hurt. I want to know what upset him and I don't understand why he is mad at me. Now mom got a letter from Nashville that they told that we had contact and that the parents could take action against us. I just don't understand my brother is 23 years old. How can the government or his parents control if we have contact?