Were the events and phenomena that preceded the mother's death—such as dreaming of her death, feeling depressed, and the presence of strange discharge on the balcony—signs of her approaching end, especially given that her death occurred just four days after the dream?

A dream may or may not come true, and no action is based upon it. What was found on the balcony wall is normal, as is the feeling of depression and unhappiness before the mother's death; it is normal and has no specific meaning. The questioner should take it easy on himself and be keen to honor his mother after her death.