You did spend a time with your father, and your family, during a most difficult time for any family---it sounds like your relationships are solid, the guilt is normal but not helpful or warranted. Remember the gardening, the moments, and you were there at the end...even had you not been, you did well....generally, when someone is so ill, they do not want others to stop everything and stay with them all the time.......life is still going on as long as a person is alive. I think you did very well. Give yourself (& yr mom etal) a big hug and thanks for being there.