A friend embarrassed me in front of others

Yesterday, I was supposed to meet my girlfriend and 2 of her female friends were accompanying her. I also asked one of my friends if he wants to join me as he has never met her and he agreed. Later, at the cafe, he didn't hold even a little bit and started with "galeechpana" (I've never seen him doing such things before). He called my gf's friends different names first and when one of them was saying that I've helped them a lot before, he said that she should be self sufficient cause when her husband wouldn't get hard will I come to sleep with her. Hearing this, I was shocked and both her friends stood and left, my girlfriend too shortly after left on her own (I used to drop her home every time).

What can I possibly do to make things better?