It could be a child who was born with ambiguous sex organs, and the parents waited for the kid to decide which way to go before embarking on surgery. However, if this is the case, the child needed to move or change schools before switching sexual identity. This is beyond ridiculous to involve other children in a personal medical problem.
If this is not the case, if it’s a real boy who just wants to be a girl at age 8, shame on every adult who has allowed it to go this far.
To me, it sounds like the kid woke up one day and decided he wanted to be a girl and the parents people responsible for him decided to play along.