Looks like he will come to know about her engagement only on her engagement day since his family is hell bent on hiding things from him ... that is, most probably he will come to know when the ring goes on her finger...how do you think he will react?
I feel bad for him... but I feel worse for her because she is trapped in this situation because of him and his family...if she had not fallen for him, if her family was not insulted in such a worse manner, if he had taken a stand on time, she will never be in a situation to save her mom's dignity by sacrificing her life