Why would he do this? I need opinions please .?

ast night my friend, who is also mutual friends with my ex called me crying. She told me how bad her boyfriend hurt her, which is also another mutual friend with my ex. She wanted mt to call her boyfriend's phone from mine because he wouldn't pick up her call. I called his phone and my ex picked up. He pretended to be her boyfriend until she relized it wasn't him. So then he asks why was she calling from my phone and she said she just wanted to speak to her boyfriend. So being the he is, he said i'm low for participating in this whole thing and he hung up. He knew whos number it was calling his friend's phone so why would he pick up and decide to even bring me in the conversation by calling me low? Is he seeking some attention?