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 at all for the person referred to as Zayd to take that money for himself from the clients without the permission of his employer. If his employer does not give him permission for this, then he is not entitled to take anything from it; rather, he should give it to his employer as this is included in the gifts of the workers which the Prophet warned us against. The evidence about the prohibition of accepting such gifts is that Abu Humayd As-Saa'idi narrated that a man from Banu Asad called Ibn Al-Lutbiyyah was working as an administrator of the Zakah, and when he brought it to the Prophet he said: "This is for you (i.e. the Zakah) but this was gifted to me." Thereupon, the Prophet ascended the pulpit and praised Allaah then said: "What is with a man that I send (to collect Zakah) so he says: This is for you and this was gifted to me? Why does he not stay in his father’s or mother’s home and see if any gifts would be given to him or not? I swear by the One in whose Hands is the soul of Muhammad, no one of you takes anything from it except that he would come on the Day of Judgment carrying it on his neck..." [Al-Bukhari and Muslim]
‘Adiyy ibn ‘Ameerah Al-Kindi narrated that the Prophet said: "O people! Whoever is appointed by us to do any job [any position] and he conceals from us as little as a needle or something bigger than it, it would be misappropriation (of public funds) and he will produce it on the Day of Judgment." The narrator said: A black man from the Ansaar stood up –I can visualize him still –and said: "O Messenger of Allaah, take back from me your assignment." He [the Prophet] said: "Why is that?" The man said: "I have heard you saying such and such." He [the Prophet] said: I say that (even) now: Whoever from you is appointed by us to a position of authority, he should bring everything he makes of it, whether little or much. Whatever he is given therefrom he should take it, and whatever he is forbidden from taking, he should abstain from taking it.” [Abu Daawood]
As regards bribery, it is one of the major sins. ‘Abdullaah ibn ‘Amr narrated that the Prophet cursed the person who gives bribery and the one who takes it. [Abu Daawood, At-Tirmithi and Ibn Maajah - Al-Albaani graded it Saheeh (sound)]
However, what is given in order to get one’s right or repel injustice is not included in bribery; and the sin, in this case, will be on the one who takes it and not on the one who gives it. Ibn Al-Atheer said: “What is given in order to get one’s right or repel injustice, then this is not included in it [bribery].”
Finally, that man must repent from borrowing money with Riba (usurious interest), by seeking forgiveness, regretting having done it, and being determined not to return to it again. A person gets what is with Allaah by pleasing Him and not by disobeying Him. For more benefit, kindly refer to Fatwa 86527.
Allaah Knows best.