My bff got her self preg on prepose!!!?

she is 17 and she was with guy who is like only 15 weird right? well she propley stop taking birth contral and told him that she was still on it they had and she got preg she told me that she wantted a baby but i did not think she would do that should i tell her parents or not her bf found out and dumped her why the hel would she do that