Me and my girlfriend are 16 but its becoming a nightmare with her parents.?

Ok, so my gf and I met through her brother. my old bestfriend, I asked him with upmost respect if I could date his sister. Me and this girl have everything in common and I mean EVERYTHING and that's why I went against my word that I wouldn't date his sister. Anyways he txted me back and said you can leave now or their will be consequences. He continually threatened me with physical affliction, that hed break me open and ruin my life mentally. He told his mom that I'm a horrible person and painted a bullsht picture.. Now can this girl stay.with me if she really wants to an disobey her parents? I mean im not provoking this she's doing this on her own. She disowned her brother because "hes not afraid to go to jail"so I'm clueless on this situation. Can she stay with me even if mama and papa say no.. I mean this isn't iraq where you have pre arranged marriages and companions.