> Also the smile my niece had when the car mechanic was explaining to him how he could

Apologies if it was just a typo, but in case English is a second/nth language just FYI that your 'niece' is your brother or sister's daughter; I think you mean 'nephew' (brother or sister's son).

(And, er, if a niece 'identifies' as 'he/him', then I would assume (but who am I to tell them etc.) they would also identify as a son and a nephew thenceforward.)