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.
First of all, may Allaah reward you for fearing Allaah and we ask Him to bless you with guidance, piety, chastity and contentment.
Love before marriage is of two kinds:
1- The love which a person did not intend or cause to happen deliberately, like a man who hears about a woman or looks at her accidentally and so his heart becomes attached to her, or that a woman hears about him or looks at him accidentally and her heart becomes attached to him; then if a person fears Allaah about this kind of love and keeps himself/herself chaste, then he/she will be rewarded.
2- The love which takes place by one’s own choice, like the case of a man who carelessly looks again and again to women, speaks to them and corresponds with them, among other means of temptation. This kind of love is not permitted in Islam, and one is obliged to repent from it.
As regards supplicating for this man to be granted good in this world and the Hereafter, then in principle this is permissible, Allaah willing. However, it might be better if you supplicate for him among the general Muslims so that remembering this particular man will not lead to unpleasant consequences.
Nonetheless, if this man is religious and has a good moral conduct, and it becomes possible for you to marry him, then this is good as the Prophet said: "The best solution for those who love each other is to marry." [Ibn Maajah] Also, it is permissible for you to seek the help of all permissible means in this regard. However, if marrying him is most unlikely, then you should endeavour to forget him and this is easy.
For more benefit on how to treat love sickness, please refer to Fatwa 84544.
Allaah Knows best.