Don't let anything your MIL says cause you any distress, Hiding, because what comes out of her mouth is par for the course.
The lengths to which some will go to in order to wriggle out of taking full responsibility for their crimes in the hope that Courts will be lenient are the stuff of legend, but he's chosen a tried and trusted classic in his attempt to explain, excuse, and otherwise minimise, his appalling assault on you.
In a nutshell, on the night he physically attacked you he was undergoing a temporary aberration; namely, 12-24 hours of amnesia caused by the proverbial unfortunate combination of alcohol and prescription drugs or some psychosis of equally short-lived duration.
As the tale unfolds it emerges that he was taking medication due to the breakdown of his marriage having caused him great distress and emotional hurt/pain and financial hardship which was intensified by living apart from his dc (on whom he dotes/adores/loves with all his heart) and further intensified by the reluctance of his thoroughly unreasonable dw (on whom he dotes/adores/loves with all his heart) to reconcile despite having previously given him every indication that she was amenable to his frequently expressed desire for reconciliation as she can't cope as a single parent.
This paves the way for the 'fine, upstanding, member of the community having been brought low through the fickleness of his dw no fault of his own and who, despite having no memory of his conduct on that fateful night, is filled with remorse as evidenced by his entering a guilty plea to all charges at the earliest opportunity' speech.
I suspect that your MIL has not only fallen for it, she's been instrumental in embroidering the tale so that the gullible others see him as a man to be pitied rather than ostracised and whose only crime was to marry a scheming bitch woman who unaccountably failed to return the love he showered on her.
Thus MIL is able to look her neighbours in the eye maintain her position in society as a devoted dm and dgm whose only concern is for the welfare and wellbeing of her poor ill-used son and grandchildren who must be desperately missing their gps and df because their dm is unreasonaby determined to punish him by withholding contact.
The only question now is how many professionals he'll be able to con will support his version of events and whether the violins will soar to the sound of him having been admitted to a pysch unit prior to sentence.