his The translation su agrees in number with the noun which it modifies. his is translated by su, sus, according to what follows: his father/mother su madre/padre; his books/magazines sus libros/revistas. For his used with parts of the body, :
his The translation suyo reflects the gender and number of the noun it is standing for. his is translated by el suyo, la suya, los suyos, las suyas, depending on what is being referred to.: