Stop watching True Blood
maybe you ought to do a private and personal farewell ritual, say goodbye to him again. take some flowers to his grave, and maybe read a prayer.
It most likely means you have been thinking about your neigbours death. Dream replay our daily activities and thoughts.
Might mean he is up there looking in on you.
Some months after my Dad passed, I felt his and my Mom's (she passed several years earlier) presence in my house. It was a warming feeling and one of assurance for me. Hopefully this was something similar with your dream of you neighbor.
Eh, just means you've been thinking about it. I notice that when I encounter something before I go to sleep I end up dreaming about it. I don't believe there is much to dreams, just things floating around in our mind in our unconscious state.