Listen to them, support them, make them feel safe / loved.
I’ve been falsely accused of abuse, rape, had a knife held at me and the use of the threat of suicide to control me. Every one of those events from different women.
The one thing I never had was true compassion from friends and family; I would not wish these experiences on my worst enemy, and I can only hope others do not suffer the same aftermath as I did.
Not just by women, but men are often abused by male partners as well. Intimate partner violence is serious and victims/survivors should be listened to, believed, and supported. Perhaps look at some resources for LGBT intimate partner violence/abuse since they may be more equipped to help male survivors and already have literature/resources aimed at reducing stigma