knows what he's doing
Él sabe lo que hace, así que déjalo continuar con el trabajo hasta el final.
He knows what he’s doing, so let him continue the work until the end.
Parece que ese tipo sabe lo que hace, creo.
It looks like that guy knows what he's doing, I think.
— O Som ao Redor (2012)
Puede ser joven pero sabe lo que hace.
He may be young, but he knows what he's doing.
— Porco Rosso (1992)
Maybe he does know what he's doing.
Y ya sabe lo que hace la gente al levantarse.
And now you know what people do when they get up.
— Open Your Eyes (1997)
He knows what he's doing.
Tom no sabe lo que hace Mary para ganarse la vida.
Tom doesn’t know what Mary does for a living.