Let me lead off that my mom has fecal incontinence and just recently appears to be moving into mid stage dementia. We moved up to the thicker Tena pads last year (she doesn't like them).
I do my mom's laundry because she can't remember how my front loading washer/dryer works. Today she added a plastic grocery bag full of panties that were so soiled with human waste that I was not willing to put them in the same machines my family uses. Instead, I threw away about 8 of them. I haven't mentioned anything to her because she'd be embarrassed and even perhaps argumentative. More likely than not, she'll forget and I will be able to replace the underwear without her realizing it.
However, while it's almost as common as urinary incontinence, there really aren't any products specifically made fecal incontinence. Do any of you have experience with this and if so, are there any products you know of specifically designed for it? (Her MD doesn't believe the pull up style will work for her because of the fecal matter spreading.)