Constant ooze of feces???

My 87 year old grandmother has come to live with me. I have noticed that every time I take her to the bathroom, she has a smear of BM in her Depend Undergarment. She doesn't have an impaction. She seems unable to push the stool out of her rectum, and instead there is a constant ooze of soft feces coming out. I have her on Miralax 3 x weekly (she gets very constipated without it), and I give her metamucil in the evening. Is this something I'm going to have to get used to, or is there a way to bulk it up and stop the incontinence?