system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do bodily functions work when someone is in a coma?
gpt
It's auto pilot; it just happens. 

It's contained and managed most simply by briefs aka 'adult diapers' if you're not into promoting respect.

Specifically for urine: Texas/condom cath to mke it easier for caregivers. Maybe an indwelling cath, but this shouldn't be used as a long term solution. A suprapubic cath is a longer term solution.

For BMs/poop: One could get a colostomy bag to manage it easier... ish.