Firefly how could he had placed an obligation on any jointly own property without her signing off on it?
For instance, if he had secured a line of credit against property he owned (a home equity line of credit, for instance), and drawn upon that line of credit, and then transferred ownership of that property to both their names, she might not know about the pre-existing lien on the property.
I personally know of a situation where that happened. It created no problems in that case because the person who had taken out the line of credit paid the loan back and closed the line of credit after the property had became jointly owned.
As we both agree, she needs to consult an attorney about her particular situation.