How should I approach my child who is attracted to his fellows?

My 19-year-old son says he likes his fellows. He was abused by a man when he was 10 years old and he didn't tell us. He fought within himself and eventually identified and accepted himself as gay. He told us about his situation this year. We did not get angry with him, but we tried to explain that such a thing could not happen. We took him to the doctor, but we could not get a result. As parents, I don't know what we should do and how we should behave. He will start working as an English teacher in another city this year. We don't want him to go, but "I don't want you, I want to live my own life." says. We also told him about the people of Lot and told about their end. He says they are doing this for pleasure, we are doing it by loving each other. Sir, I am very worried about his faith. For Allah's sake help.