@Guardian Angel Haruki
Since Brut is still convinced that he's a weretiger and therefor immune to mundane damage, could he get advantage on the save? If so, 13. If not, 3.
Brut did take everything from the shop. That would include the needle used to give him the "Lycanthropy".
If he hasn't poked himself with the needle again to take away the "Lycanthropy", he would still be convinced that he's a weretiger. So in that case, he'll have the advantage.
Unfortunately, 13 does not make the save.
The memories of his death in the previous life begin to overwhelm him as he stares into the maw of the giant fish. His body is locking up on him and screaming at him to get away from the creature.
Brutrumukk is now Frightened of the fish.