Chronic pelvic abscess after rectal cancer surgery & ostomy

My father is a rectal cancer survivor with a permanent ostomy and multiple prior abdominal surgeries. He has been dealing with a chronic pelvic abscess that has not healed.
One surgeon recommends a prolonged endosponge approach, while another recommends major surgery to remove the remaining rectum/anus and permanently divert everything through the ostomy.
Has anyone dealt with a chronic pelvic abscess or presacral sinus after rectal cancer surgery? What treatment ended up working?
We are also looking for recommendations for colorectal surgeons who specialize in complex reoperative pelvic surgery.