yes, jingi and heongjae are full-blooded brothers. The door is symbolizing c/sa.the man jingi is living with is his uncle, who is the reason why he's in prison.
raws: https://tkor098.com/%EA%B5%90%EB%8F%84%EC%86%8C%EC%9D%98-%EA%B0%9C%EB%93%A4
yes, jingi and heongjae are full-blooded brothers. The door is symbolizing c/sa.
the man jingi is living with is his uncle, who is the reason why he's in prison.