He says "a teen". It's just incorrect grammar. He could have said 'his or her heart' or 'their heart', but not every teen is a 'he'.

Still entirely possible it’s from his perspective.

Interestingly, when I was in school, we were taught that "he" could be used both for male or for gender-neutral usages.

The shift to treating he/him/his as exclusively male seems to be a fairly recent phenomenon (last few decades) as American social progressives sought to change language to be explicitly-inclusive instead of implicitly-inclusive and to avoid confusion due to the context-dependent dual meaning of such words.

1970s - "he" means everyone 1990s - "he/she" means everyone 2020s - "they" means everyone

this is also occurring in a tonne of european languages: german, french, spanish, italian, etc. it's progressives and people who care for others, not just americans.

as is well studies, we know very concretely how language and word usage influences thought (because it is thought, expressed)

Explicitly exclusive is another way of saying implicitly inclusive.

Kind of a wild take to ignore centuries of implicit and explicit exclusion of women from having civil rights.