Why would anyone forgive their sibling's murderer?

Anonymous
I read that AB Quintanilla (former singer Selena's older brother) has forgiven Yolanda Saldivar, the woman that killed his sister.

If anything wouldn't he wish to strangle that witch if he had the chance to? Link:
https://remezcla.com/culture/selenas-brother-may-no-longer-have-bad-blood-with-yolanda-saldivar/

I believe murder, rape and torture are three unforgivable things a person can do to another. Those 3 things simply have no forgiveness whatsoever. None.
Why would anyone forgive their sibling's murderer?
3 Opinion