Do skulls and red lights symbolize anything?

My friend's father died a few weeks ago. Two weekends ago he was awake in bed and saw a black figure standing near his bed. The weekend following he was sleeping (he admits it could have been a dream) but he said he saw very clearly a hazy skull with ridges on it surrounded by black smoke. This weekend he was sleeping and felt a butterfly land on his face, when he went to brush it off there was no butterfly, but an image of one on the TV. Without telling his mom this, she called him and said she saw a red light in her room and had a dream he got in a car accident. I've heard that certain objects symbolize things in dreams. Does this stuff symbolize anything besides him possibly going insane?