relative pronouns "who" and "that" used for people

The New York Times of June 15 quoted Biden as saying: “We’re approaching a sad milestone — almost 600,000 lost lives because of Covid-19 in America. My heart goes out to all those (1) who’ve lost a loved one. I know that black hole that seems to consume you, that fills up your chest, when you lose someone (2) that’s close to you (3) that you adored.” Are the numbered three relative pronouns “who” and “that” interchangeable? Or is there any difference in nuance between them?

Solution 1:

That is routinely used as a relative pronoun equivalent to who for people or which for things and abstractions. There are those who will complain at calling that a relative pronoun; they have a point -- it used to be a complementizer like the that in

• I think that I shall never see

The complementizer that used to appear in all subordinate clauses, like the that in Chaucer's

• Whan that aprille, with his shoures soote

It sounds strange to say, in modern English, When that April is over; what's the that for? It still exists, though, in local dialects, In relative clauses, it wasn't necessary to mark the clause as subordinate, so it got re-used (as small pieces of grammar are -- look at all the chunks beginning with wh and th still around today.)

That and Wh-words are not completely interchangeable in relative clauses. In restrictive clauses, they are, and you can use that anywhere you'd use a Wh-word. But only Wh-words can be used in non-restrictive relatives; that's one way we mark non-restrictive relatives now, along with the comma intonation before (and after, if they're not final).