Suggest Treatment For Knee Pain In Elderly

My grandma's age is 70 and her height is 5'5",weight is approx. 45-50. from past 2 years she is suffering from knee pain. her knee pain has increased in a few days and she is unable to stand ,sit and walk properly as she used to do before. she suffers from vertigo on standing up. from past 2 days she is getting muscle spasm or somewhat that type of pain in her muscles on doing simple works as well. please provide some medicine if possible or some workout to decrease her pain. thanks.