When referring to a particular person what relative pronoun should you use?

The relative pronouns for people are who (subject), whom (object), and whose (possessive). The relative pronouns are used for any person. For example:

My brother, who is a year older than me, is entering college this year.

She can't remember the name of the person, to whom the letter was sent.

Janet, whose mother is making the cake, will bring it when she comes.