Seems that it must me quite difficult for your mother to chew and eat properly because of which her overall health must be also effected. It's high time to visit your dentist and get a thorough check up done which will decide the plan of action to rehabilitate your mother's oral condition.
Next Steps
Fix an appointment with your dentist ASAP and understand wether teeth can be saved or its better to get them extracted and then rehabilitate.
Health Tips
If she's suffering from some medical conditions take the records with you also prescription of drugs if she's under medication.