Most peoples bowels do release when they die.
If the person who dies has poop in their bowels then when they die the muscles of the bowels will relax and then they will poop when they die.
So if you work as a funeral worker in the funeral home and have to prepare dead bodies then you may experience the need to cleanup poop from a dead body.
It can be gross for some people but some people have no problem dealing with it.
Also some people when dead will also pee in their pants as the persons bladder muscles relax as well.
It's a normal process but if you have no urine in your bladder or poop in your bowels then you may not pee or poop when you die but it does happen.
The process is entirely normal but may be upsetting to some people who are not used to dealing with it.
When the body dies some dead people will have poop release from the rectum, urine from the bladder, or saliva from the mouth.