Reason for my friend's isolation

We just spoke more on the phone more then we did face to face. He got into touch with his other friends but after they didn't bother with him, he sank deeper into isolation. My friend prefers to be with friends in person more then talking on the phone. When we have been together in person, he is very happy. He even admitted to me once in a conversation, that he was happy being with me. Part of my friend's condition is having mood swings. His father is the kind of person, who will snap at him for being moody. You speak only when I say and if you are rued to me, you will get a rued comment said at you. That's what my friend's dad is like. So my friend thinks he is a bad person to be around with. So he avoids all social contact because of his bad experience with his dad.

We used to talk a lot to each other on the phone. He doesn't feel comfortable with hanging around with females due to low experience. When I went down there to speak to him, he was listening. I got in touch with his mum and asked her to contact me to let me know how he was doing. She phoned me and I could hear him lauging, giggling and blushing in the background. His mum said, he was extremely shy to talk to me.