Open heart surgery stats

My brother had successful open heart surgery 17 years ago. He has been in good health ever since, walking 3-4 miles each day, stopped smoking. Recently, his doctor changed his medication, and our mother, age 86, thinks there must be something wrong. She "heard" "somewhere" that once a person had open heart surgery, they could only expect to live another 15 years, so my brother must be on borrowed time. Is there anywhere I can get statistics showing that people with successful heart surgery may live a long, long life? He is 64 now.