The article is a wee bit of a red herring. Marriage would have protected her if they'd spoken openly about their finances. She'd have known that a) she wasn't the beneficiary of his life insurance policy and b) there was paperwork to say that in the event he died, the debt to his dad would have to be repaid in full.
Really, the husband had not made any provision for his wife in the event of his death. He was only young and died totally unexpectedly but I'd say it was normal, if you're pooling your finances to also make provision for one of you dying.
In the article she does say she would consider herself to be 'almost negligent' in not knowing about much of this.
Marriage does offer good financial protection but only if you're completely transparent with each other and make sure that all your legal ducks are in a row.