What Causes Clear Liquid Fluid Discharge From Rectum?

My brother is 75 years old and has recently had an issue with clear fluid leaking from his rectum. He went to his doctor about two months ago and was diagnosed with a condition (can t remember the name) and given antibiotics and a steroid, I believe. My brother is an avid bike rider - at least he was before he had this issue. His condition improved greatly and although he is in no discomfort, he has recently noticed a clear fluid that leaks from his rectum. This usually occurs in the night or while he is using the bathroom. He has an appointment with his regular doctor but it isn t for two more weeks. Do you have any suggestions? Should he wait the two weeks or try to get in to another doctor sooner?