that would be a definite NO. Please advise her not to get confused that this particular relationship is love. Maybe she does but no guy could bare to hurt a person he truly loves. Also if this particular guy starts with the sob story of 'Í'll promise I'll become a better person'; DO NOT believe him. Maybe for a few days or weeks he'll be on his best behavior but afterwards he'll be back to normal and will continue to abuse her. Also a common trend is that they normally get more and more into it.
If you have some influence on her, stop her; she may hate you for it but it's better to be the bad guy than have her live with an abusive partner. I wouldn't want to wish it on my worst enemy.