Another dimension to this story. I lost my wife at badrinath 2 years back, my son and daughter (aged 19, 17) were with us. kids had a fight between themselves and mom scolded my son and asked him to apologise to his sister, he refused. next morning my wife expired suddenly. wife and my son were very close. it is now two years and my son has yet not forgiven himself that the he did not follow the last instructions of his mother.
Dont wait another day to apologise , you may never get a chance.