Need referral to urologist

My brother was born in 1968, he had a paracitic twin and they would have been attached at the hip. He is now 43 years old and has had multiple surgeries to correct the multiple birth defects from the twin. he is currently having an issue with his bladder and urethra and is seeing a physician in Philadelphia. We are not happy with his care and are looking for the name of a physician in our area whrer we could get a second option. We would prefer to see someone at Johns Hopkins. He was treated by Childrens Hospital of Philadelphia for most of his life, but several years ago they told him he needs to find another set of physicians to care for his multiple problems.