Question: A man has partners in an estate who are orphans. He undertakes to grow and manage the wealth, and substantial income is obtained for him and for his orphan brothers through that. Is it permissible for him to lend something from the estate in the manner commonly practiced? And is it permissible for him to give to the beggar and the needy and the like, which those who possess wealth are usually tried with?
Answer – and Allah is the One who grants success: What appears is that the man mentioned in the question is permitted to do what is mentioned in the question, on condition that he does not exceed the customary limit; and it is not permissible for him to give to the beggar, the needy and the like more than such people are ordinarily given by someone like him.
We have only said that this is permissible because of the common custom of feeding and honouring the guest, and giving to the beggar, and the like. The scholars of the madhhab have mentioned something similar regarding the slave who has been given permission to trade, as in the Sharḥ. As for a partner of the orphan who does not undertake to manage and grow the wealth, it is not permissible for him to give anything from it.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2