How do I make my 26 year old sister break up with her 42 year old boyfriend?

So my sister is in a relationship with this guy who happens to be 16 years older then her. I say it's weird I want her to go back with her ex boyfriend but she says she wants a real man not a boy now how is a 25 year old a boy that's a man that has had life experience and mature. Now I called her ex boyfriend I told him a lie that my sister wanted him back. I decided to invited my sisters ex to Starbucks and my sister but she didn't know her ex. When my sister comes in things got worst me thinking I was for the better. Thanks to my sister now her ex got angry at me and he called me a liar which I am not all thanks to my sister. My sister yelled at him she told him that he was immature, disrespectful that her feelings for him have been long gone. All I know they broke up in 2012 . According to my sister she tells me that this 42 year old boyfriend was there for her during this past 6 years when she was going threw a hard time in her life as the years went on she ended up having feelings for her now 42 year old boyfriend. It was uncalled for my sister to treat her ex she said she never wanted to see her ex. Come on this man is old enough to be her dad, Oh my sister got so angry she won't talk to me answer my text or phone calls. How do I make my sister break up with her old man?
How do I make my 26 year old sister break up with her 42 year old boyfriend?
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