Strange Family situation

Hi, this advise is about my bro who just turned 40 this month, the problem is when he was 19 yr old he fell in love with a girl J and forced our mom and dad to marry J or else he will suicide, my parents so naive fell into threat and got him married to this girl J, the girl J was no match to our family and no one liked her despite the marriage happened, after been married to J for couple of years my brother went on with his life and got busy working on his business and was unable to give so much time to J, working late and early mornings were his habits, during this time they started having arguments, in my bro's absence J started seeing a boy who lived in the opposite building and meeting him, exchanging gifts, talking on phone, as my brother came to know about it he also found someone else and started seeing other girl, during this time J started suspecting my bro and got herself Pregnant hoping that things will go back to normal, inspire my brother moved out of the house and started living with this another girl D and left J with Parents and myself, since J was pregnant my mom and dad did not say anything to J and tried to argue with my bro to come back home and take his responsibility but my bro did not come back and instead said he wants to marry D and never wants to do anything with J, J started giving Suicide threats to my Mom and dad, my mom consoled her and to carry on with life, took care of J during the pregnancy and childbirth, my brother has started new life with D, got married with D, now and he does not want anything to do with J or the child, me and my parents helped J during this time, supported her provided everything she needed. She wanted to have my brother back, we could not bring the brother back for her. Meanwhile J's family got furious and threatened my parents that if their son does not accept J we will file Police complaint against you and you guys and have you arrested and J's brother is known to have a criminal background said to my parents that he will get my bro killed or send him to jail, my parents again tried to convince my brother but he do not want to return home to J, so Parents agreed to take care of J and told J's family that we will take care of her and the Kid, fast forward 17 yrs. now my parents are still living with J and the Kid, i got married and moved away from my family, the Kid is now 16 yrs old, but here is the problem, my Parents have bought a house on J's name and they all live in that house, now J doesn't want my brother to visit his own parents, J doesn't let my parents talk or meet my bro or me, my family is ripped apart to please her and trying to make her happy, my parents are separated from everyone, how can my brother get his parents back, he still don't want to live with J, he has a son with D and living happily with D for 17 yrs now. J is not willing to Divorce him. please advise how to reunite mom-dad-son, they are senior citizens now and living very stressful life with J.