his

1

This is him coat.
This is his coat.

His can be a possessive adjective, also called a possessive determiner. We use it before a noun: ‘This is his coat.’

2

This coat is him.
This coat is his.

His can also be a possessive pronoun. In this case, we use it without a noun: ‘This coat is his.’

Unlike her/hers, the form his is the same before a noun and when it is used alone.

See MINE