immigration query

[NLE]

I have a query, not sure if this is the correct forum, or even type of forum, but here goes:

I came in to contact with a woman (friend of a friend type thing) who has been residing here in the UK for nearly a decade, having first come over (from non-EU) with her UK citizen husband. Just prior to being able to sign the relevant forms and become a UK citizen after being here a while, her husband left, and she has been residing here, under the radar, for nearly a decade, having not left the country since.

She really wants to stay, work, pay taxes and so on as a legal citizen, but doesn't want to be deported. Does she have any options?

If anyone has any info it'd be much appreciated.

[Casa]

'Just prior to being able to sign the relevant forms and become a UK citizen after being here a while'. She would need to have applied for permanent residency (ILR) before qualifying for British Citizenship. I assume she didn't do this?