My dad is 67 over the last 30 days he has had pain in the right side of his waist down his leg to his ankle wondering what this could be?

Bulging disc: What you are describing is most likely due to a bulging disc in his low back. Another possibility could be arthritic changes in the spine affecting the nerves. Should get an x-ray of the spine possibly an MRI. Depending on his health and other conditions, anti-inflammatory medications may be helpful. Manual treatment can be helpful. Exercise and physical therapy could also come into play.