There has been a lot of bad behavior blamed on post natal depression and post natal psychosis certainly but they are not phony illnesses. Now Post Natal depression generally can’t be used as an excuse for immoral behavior. A person is generally not robbed of their free will and moral restraints and while deeply depressed are generally oriented to themselves and know right from wrong...how ever some do become suicidal.
Post Natal psychosis is a really nasty issue and I’ve encountered it several times in my nursing career. Some never recover, can be injurious of themselves or others including their newborns or become totally disassociated from reality and become completely withdrawn from everyone and from themselves. They can become murderous.
Post Partum blues or depression is definitely what this person did not have.
You named it.