317 Over 65 divorced mother not widow, which ruling?

My Partners mother was refused a permnanent visa to settle in the UK from China. Is there a ruling that divorced over 65 can be considered under another rule in paragraph 317 dependents visa

- 75 years old
- Single by divorce (father remarried) in 2000
- Recieves a minimal monthly divorce payment (£25/month 10 days food)
- We support with £2-3k/ year on annual visits
- she has only 2 daughters both settled in UK with own homes, no dependents and good jobs.
- she owns no property and lives in a residential home.

refused on grounds she didnt fit 317a)-f) as divorced and not a widow or remarried.
Also payments were mentioned from divorce see above.

Is there any ruling for a divorced over 65 to be considered in a category and not just refused?