At your age, ongoing itching and dryness in the vaginal area is usually from naturally low oestrogen after menopause, which thins and dries that skin and makes it more prone to irritation. The relief you get from coconut oil fits that pattern, since it's acting as a simple moisturiser.
Next Steps
A vaginal moisturiser used regularly, not just when it flares, usually helps more than oil alone. Your gynaecologist can also rule out a simple infection and discuss whether a vaginal oestrogen treatment would help.
Health Tips
Please see your gynaecologist soon if you notice any bleeding, a bad smell, or if the itching keeps getting worse despite this.