What Causes Uncontrollable Whiteish Rectal Discharge, Especially Given The History Of Lymph Node Removal For Breast Cancer A Wile Back?

My mom is having a strange uncontrollable whiteish discharge from her rectum. She woke 3 times in the night with wet underwear and when she stands up it just comes out. She has a sleeve on her arm for releasing fluid from her underarm lymph nodes removed from breast cancer in 2019)