Tier 2 dependent Visa expiring soon - maintenance fee not met

[chipromos14]

Hello everyone. A friend of mine is in a pickle and we will appreciate some help.
Background:
She entered UK late 2014 on tier 2 dependent Visa. Since then, the main appicant is now a British Citizen, and they have 2 BC children too. Live together in a real marriage.
However, the husband lost his job many months ago and currently on benefit due to health issues. My friend has been on maternity leave but will be starting a new job shortly.

Issue:
Her Visa expires next month and I have just realised they don't meet the maintenance status for her. Am not sure what else to do about it now. We have managed to make up the £630 today, but the Visa expires end of April.

My question is: can she apply for discretionary leave to remain under family ties, and once the 90 days is up she varies it to the tier2 dependant Visa? Is this allowed?

Thank you in advance for your help

[chipromos14]

Please can anyone advise?