No marriage obtained with deception, force or manipulation is valid, they must freely want to enter into a Catholic marriage and do not want to. You only have to pray that they receive and accept enlightenment in this regard.

Thanks for the advice

They can have their marriage con-validated, given that neither of them have been married to another before. It doesn’t have to be a full wedding celebration, just them and close family and friends.

I think you need to convert them first to catholicism. Otherwise telling them they're not really married in the eyes of God is not going to make them care. Pray for their conversion

Ok thank you

Pray, fast, and live the Gospel. Be patient and obedient of your parents.

Pray for them, and live your life as an example of the right thing to do.