Why not "He seats" ?
Could be 'he' too. Dia means he OR she. but seat means the thing you sit on. (kursi)
it's a neutral word; dia can mean him or her (fyi ia too - it's also like dia)
Dia is he/she and ia means he/she/it but ia refers more so to animals than a person.
He seats is not proper English and makes no sense, so it would not make any sense to say that.