They’ve been dating for about 5 months. They’re relationship isn’t toxic exactly, but he’s constantly grounded (they’re 17) and when she tried to say how hurt she is or how it’s impacting her, he just goes on about how much more hurt she is. 

She talks to me everyday about their constant arguments. It’s gotten to the point where the insecurity she has in her relationship is fucking up everyone else around her. 
I want to tell her to break up with him, but don’t want to make the wrong decision. Help!! 