Luckily you DON'T have to close all the deathcare facilities down and wait for all the super hearses to come back. You just exit the game wthout saving, unsubscribe from this mod and then once you relaunch the game, all the super hearses are gone and you are back to the normal 10-capacity hearses and are all being sent out from all the facilites.

I thought after all those time there would be some updates to correct this problem but nope. I just downloaded this mod and just like Chirs.Hill said, once the super hearse is in use, those cemetaries and crematoriums just don't bother to send out hearses anymore and just let this one super hearse doing all the pickups and all the dead bodies just pile up. I never thought a city management simulation game would turn into a game of picking up trash and dead bodies. The simulation engine of game is COMPLETELY broken!!! Can't believe all the cims just die all at the same time and you are stuck with one death wave after another. This is so stupid and so frustrating!!

Higher texture please

They may be an issue with this. Since the capacity is much higher than the standard hearse, the system seems to think that it does not need to send out so many hearses. That is good for normal conditions, but becomes a major issue with a death wave, where you cannot collect bodies faster than they appear. Eventually you find that there a dead bodies everywhere and buildings get abandoned.
To remove this vehicle you need to close all of the cemeteries and crematoriums, and wait for all of the hearses to return to base. There also seems to be an issue with the Traffic Capacity mod which crashes on load if you remove this vehicle with a problem with AIBus.