What are the chances of someone living visiting you in a dream?

Pretty good. It is a common way for some folks to keep in touch. Rarely is it an intense conversation about earth-shattering things. More often it is a desire to:

1) know someone you care about is well

2) Let some one you know know you are thinking of them

3) a reaction to fear or danger - the message then is "Need you"

4) some times it is an exercise to expand your mind and its powers. it is easy to contact someone you know that to contact a stranger (and someone you know will often call or let you know they saw you in their dream, thus letting you know your mind exercise is working).