My older brother is grossly incontinent and it's complicated. Physical anomaly, on the autism spectrum and will NOT wear anything different, his wardrobe choices NOT conducive to pull-ups, can not make it to the bathroom on time due to severe knee issues. Needless to say, maintaining the bed and floor in his room and home is a major problem. (He lives with our 91 y/o mom. Between my cleanings, it is unsanitary for both.) A couple of years ago (pre-COVID) I wrote his urologist asking him to address this problem (I have healthcare POA) , hand delivered to the clinic and know it was scanned into the chart. I think he has a bit of anosognosia going on here ("I can't help it," and that is true but he has no interest is resolving the issue.
I think he might benefit from being on a schedule for going to the bathroom? Like every X (2?) hours, whether he thinks he needs to go or not. Just go. Try. You can always pee a little!
Maybe a commode or a urinal? Is it so bad that he would need a catheter?
Can his knee issues be addressed?
I would hire an aide, especially to clean up the accidents so it is not so unsanitary.
Sounds like a handful!