# For the unbelieving husband is set apart because of his wife

Possible meanings are 1) "For God has set apart the unbelieving husband for himself because of his believing wife" or 2) "God treats the unbelieving husband as he would treat a son for the sake of his believing wife"

# the unbelieving wife is set apart because of the brother

Possible meanings are 1) "God has set apart the unbelieving wife for himself because of her husband who believes" or 2) "God treats the unbelieving wife as he would treat a daughter for the sake of her husband who believes" 

# the brother

the believing man or husband

# they are set apart

Possible meanings are 1) "God has set them apart for himself" or 2) "God treats them as he would treat his own children"