Gaslighting is deliberately recalling history incorrectly to confuse the victim into thinking they are wrong. It’s a very subtle and powerful form of emotional abuse, as the victim loses their sense of self and unwittingly ends up relying on the abuser. You lose your identity, self worth, and end up with chronic PTSD if the abuse and other forms of associated abuse is also present.
I would encourage your friend to educate himself on forms of abuse.
The law is not in men’s favour at this point. In my case, my ex wife alleged I was a criminal, I was then arrested, bailed with conditions meaning I could not return home and she would only allow me to see the children 1 day a week. As a result of her ringing the police alleging domestic abuse, she was then entitled to apply for legal aid, and as parent away from home I now have to pay full CSA.
I would advise your friend to proceed with caution. Start by making notes regarding there behaviour and emailing them to himself so they are date stamped.