While "rev" might seem like a separate root, it's actually part of a broader meaning of taking away forcibly. This is why "bereave" signifies the act of being deprived of something precious, especially a loved one through death.
Here's how the root word evolved:
* "Reofian" (Old English): to tear off, plunder, rob
* "Reofian" (Old English): to take away forcibly (especially someone's life)
* "Bereave" (Middle English): to deprive of something precious, especially a loved one through death
Therefore, the root "rev" in "bereave" signifies the act of taking something away forcefully, which ultimately connects to the meaning of being robbed of a loved one by death.