All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is not permissible for a Muslim to have an affectionate relationship with a non-Mahram woman as we clarified in Fatwa 81356. Therefore, this young man is obliged to repent to Allaah. He should be careful not to follow his emotions as he might be cheated by this girl who might embrace Islam for the sake of getting married. Then, when the marriage is concluded and some problems occur in her marital life, her matter would be disclosed and she might even apostate. Therefore, we advise him to be rational and not affectionate.
However, if this girl embraces Islam and she is sincere in doing so, then he should try to convince his parents to consent to his marriage to her. First of all, he should seek the help of Allaah and then the help of whomever he thinks may influence them. If they accept, then this is what is required, but if they insist on refusing, then he is obliged to obey his parents unless he fears to be tempted by her, in which case, he may marry her and then try to please his parents. For more benefit, please refer to Fatwa 85736.
As regards committing suicide, then this is forbidden and it is one of the grave major sins and by committing suicide, one loses this worldly life and the Hereafter; indeed, we clarified the evidence of its prohibition in Fatwa 81819.
How could this young man grieve his mother who carried him in her womb, breastfed him, nurtured him, offered every precious and valuable thing to him and faced every kind of difficulty for his sake? Is it for the sake of him marrying a girl whom he does not know whether or not she would embrace Islam? Even if she embraces Islam, he is not sure that she will become pious. Even if she is pious, he is not sure that he will be happy in his marital life with her.
To sum up, if he loses his mother, he cannot find another mother, but if he loses this girl, he can find many other women. A mother and a wife can never be the same. For more benefit, please refer to Fatwa 87019.
Allaah Knows best.