Found this book in a "little free library" - left by someone fighting the hoarding demon? -- my mom told me about them as a kid, perhaps as a way to motivate me to keep my room clean.* As a side note, I enjoy what is called trivia (though I've never won anything in one of those contests) - but there a good one here - the brothers are buried in the same cemetery as - are you ready for this -- Mae West, Jackie Robinson, Piet Mondrian, P T Barnum & Gentleman Jim Corbett - wow, what a star studded burial ground! - An entertaining video game might be Marie Kondo vs the Collyer brothers.
Book also has observations on the de-gentrification of Harlem at the turn of the last century. One reviser complained that the books had to much a extraneous stuff about Harlem, which I found quite interesting - reminded of a comment on "Moby Dick" that it was a great book except for the whale parts - hey, those were the best parts!
In summery, this is a sad tale, with, alas, no happy ending
*it worked - I'm not a hoarder, although I do same more stuff than I ought - hay, I might need it some day, right!