If he is in old age, then here are the options
1. Extraction , if his health permits and go for implants.
2. Without extraction option is Go for professional cleaning and do splinting along with incisal reduction.
3. If there is any infection , then better go for extraction to avoid any health issues due to this.
Next Steps
Please visit dentist and ask for the above mentioned treatment plan.
If he cannot walk ( due to age), please book for online consultation prior to treatment.
Health Tips
Maintain good oral hygiene to save other teeth.
1. use soft bristle brush
2. Brush twice daily
3. Professional cleaning must.
3.Give gum massage with Gumtone paste( only for gums) to save other teeth.
4. Apply sensodyne paste( teeth only)
Hope this helps you sir