Were Barrett's family interviewed for the book?

I believe so, although I don't know to what extent— at least his brother, who is mentioned in the acknowledgments and has also written his own book— and Emerson also mentions/quotes from interviews with Barrett's friends. Sadly, it seems like his parents didn't really have or take the chance to push back against Sparks' narrative while they were alive...? Apparently they did sit down with/try to confront her at one point after she published Jay's Journal and Sparks flimflammed them again (claiming the whole occult thing was based off interviews with his friends, ironically) to avoid having to apologize or retract anything. :(