What is the SD on dissociative identity disorder

My mum is currently reading this book on dissociative identity disorder in which it is claimed concerning the author:

This all sends my BS meter off the scale, and reminds me of the infamous (and now thoroughly debunked) ‘Sybil’ case, and as well as other infamous"false memory" cases, but I can’t find anything debunking this particular case.

Ignoring the religious aspects (it is a Christian book my mum heard about through church) would any reputable mental health worker stand by a diagnosis of DID like this?

Cecil’s column from 2003

See also:

Experiences with Multiple Personality Disorder?
Anyone have information about DID? (Disassociative Identity Disorder)
Interesting article by a woman with Dissociative Identity Disorder
What medication is used for Multiple Personality Disorder?