Hello ma'am
1. Using a toothbrush and toothpaste once daily for dentures is a good practice. Also, they should be kept in plain water at night.
Flossing is not required for dentures.
2. Simply cleaning the gums daily with a clean finger is often good enough to maintain oral hygiene if no teeth are present. Toothpaste is optional
3. An adult broken tooth will not repair itself or grow back
I hope these answers were to your satisfaction. You can contact me for any further queries. Thank you!
Next Steps
It seems the questions for on behalf of an elderly person. Do direct them towards a dental clinic near you