Lymph node cancer after complete bladder reconstruction

My brother was diagnosed with bladder cancer 2 years ago and had UCLA do a complete bladder removal, reconstruction and Chemo Treatment.  He has been cancer free until today.  He was told that cancer had returned to the lower lymph nodes on both sides of the abdomen. Surgery and  Radiation appears to be the treatment since he had a heavy dose of chemo the first time.  My question is "is proton beam treatment" after surgery a viable option?