Such things not happen in one day, it was building before and now it's reacting.
Anyway now you have to act normal and caring to him, don't lose ur son. If that girl accept Islam then ask your son because going against his will can't work.
Do tawasul with Ahlebait AS and read hadees e kisa 40 days.
My son fell in so called love with a hindu girl in his class. I asked him but he always lied to me that he is not having any relationship. While leaving for hostel I found love letters and cards from his bag and I told him that this is haraam relationship and will not be accepted by us at all. I secretly removed the letter and cards from my son. When he came to know about it since then he is not talking to me and doesn't want to keep any relation with me. He is a typical boy who doesn't want to follow any religion and he also doesn't like us (his parents) for we ask him to offer namaaz and religion. I am very troubled how to get him on the right path. I am too worried as since last month he hasn't talk to me
No doubt your situation is very sensitive but first of all you have to take your boy in your faith.Please do not force him a lot try to convince him that you are his well wisher not an enemy he is in extremely sensitive age but he is not only boy who is behaving that.There are many boys who do same in this age. You sit with him and with full confidence and calmness talk with him.Give him examples and make him understand that what he is doing is not important but because he is still so young and there are many challenges he has to face in his life so first he has to concentrate on his career then when he will reach to the age he could do what h wants to do.Do be too much inquisitive about him and even don't make him realise that you are chasing him. Keep yourself close with him.Ask him about his favorite food if he wants to eat make for him.
My son fell in so called love with a hindu girl in his class. I asked him but he always lied to me that he is not having any relationship. While leaving for hostel I found love letters and cards from his bag and I told him that this is haraam relationship and will not be accepted by us at all. I secretly removed the letter and cards from my son. When he came to know about it since then he is not talking to me and doesn't want to keep any relation with me. He is a typical boy who doesn't want to follow any religion and he also doesn't like us (his parents) for we ask him to offer namaaz and religion. I am very troubled how to get him on the right path. I am too worried as since last month he hasn't talk to me .
Leave him in the hand of Allah swt and ask Him to guide him and bring him to you.
That has worked with many mothers, for Allah swt can what we cannot not.
Do not push on him any thing just keep good respect and kindness. If he has chosen something else we cannot do much.
Pray pray and pray until u get him back from Allah swt do not give up.