Personally I believe that Joseph had died and Mary was a Widow. Since Jesus was the first born, it would have been his responsibility to take care of his mother. It is noted in John 19: 26-27 26 When Jesus therefore saw his mother, and the disciple standing by, whom he loved, he saith unto his mother, Woman, behold thy son! 27 Then saith he to the disciple, Behold thy mother! And from that hour that disciple took her unto his own home. From this it is indicated that Jesus turned the responsibility of looking over his mother to John, as John is mentioned as "the disciple whom Jesus loved" If Joseph was still alive, Jesus wouldn't have needed to turn over the responsibility of having someone looking over his mother turned over to John. As Joseph would have still been able to provide and care for Mary.