As a non-Catholic he was free to be married anywhere. His exchange of consent at his first marriage is presumed valid (canon 1060) until proven otherwise (i.e. annulment). Since he is presumed to still be married to his first wife, he is not free to enter into another marriage. He fist needs an annulment for his first marriage and then he and the Catholic party need their current civil marriage validated in the Church. If he is divorced but his first wife is deceased, he is then free to marry since marriage is until death.
Once they are in a valid marriage the Catholic party may receive communion.