Lol, I personally thought the ending was extremely implausible and conjured up just for “shock value” … suspension of disbelief be damned. My issues with it are (SPOILERS follow):

— no mother who isn’t a psychopath would write about how she killed her daughter as a “literary exercise” … not three days after daughter accidentally drowns, not ever. Not buying it at all.

— no one prints things out anymore, let alone print something out with false confessions of murder and leave it just floating around the house

— no grieving mother could keep up that charade of being brain-dead for as long as Verity did. It’s impossible.

— only a psychopath mom would inflict upon her grieving son the “brain dead” charade, making Verity a villain regardless of whether the autobiography was true

— if Verity’s deception of being brain dead was so critical, why did she risk it by appearing on the stairs while her husband banged Lowen, by walking around at night, by waving at her son … it makes no sense as any of those moves would have most likely blown her cover

— how did Verity set up a secret new bank account and then get her publisher the wiring instructions if she was supposedly comatose?

— a woman of Verity’s wealth would not need to “wait until the wire hits the bank” in order to flee town with her son.

— from a “literary” perspective, the way Verity delivered all that exposition in her letter, much of it already known to her husband the intended recipient, was just awful writing, not to mention how convenient it was that the letter was found at the perfect time for the conclusion

— I can’t even remember how she supposedly rigged the car wreck

BUT, with all that said, I did kinda really enjoy the ride until the last 10 pages.

Also, did you notice the 8th book in the series was to be called Truth? My theory is the book “Verity” is actually Book 8 in the series as Verity = Truth.