The most important is taking care of their health, please make sure that your parents getting proper medical check-ups and treatment. Kauvery hospital provides NRI Parents Health Care In Chennai that focuses on providing comprehensive care for seniors in case of an emergency. Other than this you have to:

Choose priorities wisely

Allow independence and choice

Have patience with them

Make time to be with them

Try not to hurt their feelings

Keep their complaints to yourself

Try to simplify their lives

Love them to pieces