Try to determine what is really wrong.
In a very sad video a girl came out as trans to whoops, cheers and screams of I love you. This poor child was about 12, fat, homely, with an unattractive haircut and dressed like a fat adult instead of a 12 year old in clothes that didn't fit. Clearly this child had suffered immensely. She must have been teased and bullied beyond measure. When she said "I'm a guy" it all changed. People weren't teasing. They were screaming that she was loved, cared about. How she really felt was immaterial. She now had a safe space.
If my 14 year old son came out as gay or trans I would first try to find out what was really wrong.