How Can Kidney Rejection Caused By Rising Creatinine Levels Be Avoided?

Hi. my brother who is 40 yrs old has had his kidney transplanted 6 yrs back. but now his creatinine level has risen to 380 and a biopsy has revealed that his transplanted kidney has shrunk slightly. his doctor says that this will ultimately lead to rejection. i would like to know if this can be avoided. please advice. thanks in advance