Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh.

 

It seems that your sister fell in love with this man. I think your role is to see if this man is really a good choice for your sister by making sure of his religion and character and making sure that his family will not make troubles for your sister in the future, you should take all possible ways of convincing your parents of at least opening the door for him or at least listening to him.

 

You should in this case warn them of deteriorating consequences which may happen such as your sister’s situation, her refusal of future proposals, her psychological situation and possibility of getting married to him in secret which may lead to a big problem at the family.

 

On the other side, if you think this type of marriage will not be successful, you should talk frankly to your sister that it may cause her a big problem in this life by dissevering ties with her family, getting the wrath of Allah because of disobeying parents. You must help her get rid of thinking about him by all means possible. Reliance on Allah, keeping one busy with prayers and supplications.

 

Almighty Allah knows best.