Permissibility of a father paying for his son who works with him

Q: I have many male and female children. I asked my youngest son to stay with me to take care of my camels and sheep, fetch fresh water and take care of me. I stipulated that I will give him a she-camel for every year he spends with me as a reward for his efforts because his brothers left me to seek work but he obeyed my orders and stayed with me for almost three years. Now, he has three camels. Is it permissible to single him out for something in return for his efforts? Could you kindly advise me in this regard. May Allah reward you best?

A: If the reality is as you have mentioned and that his service was proper to the reward you stipulated, there is no harm to give him the she-camel in return for his efforts. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.