Or if there is no mother due to any circumstances, but it's convenient that he left out what "a certain age" is, and I don't know that it is "supported" insofar as doing it for the fuck of it.
You don't have to bathe a kid that many years before they can do it on their own, outside of extenuating circumstances like injury, deformity or mental illness and it's certainly not something you'd really rush to the defense of others doing as if it's some normal and expected things.
Up to a certain age means if it's a baby and you need to wash her and mom can't for some reason... otherwise it gets weird very fast
Or if there is no mother due to any circumstances, but it's convenient that he left out what "a certain age" is, and I don't know that it is "supported" insofar as doing it for the fuck of it.
You don't have to bathe a kid that many years before they can do it on their own, outside of extenuating circumstances like injury, deformity or mental illness and it's certainly not something you'd really rush to the defense of others doing as if it's some normal and expected things.
If the girl can shower she's definitely too old for her father to be even in the bathroom, let alone in the shower with her.