Getting a travel document or not depends on the reasons why she could not meet the residency requirements. If she has mitigating circumstances for staying outside Canada too long like taking care of a sick relative or inlaw and can prove it, she may be granted a travel document. If she has no mitigating circumstances, then she will be refused and will most likely lose her PR. Her husband can sponsor her for PR again but only if he meets the requirements himself. If he also has 6 months until he meets the requirements, he would have to wait. A sponsorship can take anywhere from a few months to a couple of years.rpk said:
If she is visa exempt, she would be able to get into Canada again without applying for a travel document. She would simply fly to Canada without telling the airline that she is a PR and at immigration she would provide her expired PR card, apologize of not having been able to renew it, say she did not notice it was expired. If she is not visa exempt but has or can get a visa to the US, she could fly there and cross the land border again to Canada with the expired PR card.
Lets say taking this trip now, she risks losing her PR. There is no guarantee that she will be given a travel document when she does not meet the residency requirements.