She had multiple episodes with the guy but all kissing and heavy petting(petting... such an old word). Then one day it went further. He rubbed her bare breasts and she put her hands in his pants. She stroked his penis and he almost had a happy ending.
someone who had committed fornication and never repented officially. This nullifies the marriage bond.
Heavy petting, or whatever it's called now, is NOT fornication. In JW land, fornication = penis in vagina. Touching, fondling, stroking, kissing is not fornication, it is technically classified as loose conduct in the Elders' Manual™ - that's why so many effing child molester JWs get away with that $h!t.
It doesn't nullify the marriage bond. Clearly she was repentant - she cried and turned her life around immediately. Just because she made the choice not to submit to personal humiliation in front of three adult males and possibly get DFd and kicked out of her parents' home, doesn't mean that she didn't make her peace with Jehovah™ before meeting your friend. It seems like a no-brainer that if she had felt it was a big enough deal, she would have talked to him about it before they got married - and I'm personally wondering if your friend has some 'splainin' to do about his past as well.