Co-operative organization is governed

Q: There is a Bedouin family consisting of a blind man, his wife, and their son who provides for them. The son is very poor and has neither a steady job nor is he married. In light of the situation, some people decided to collect money for this dutiful son so that he could get married in order that his wife might assist him in looking after his parents. These beneficent people collected a sum of 20,000 riyals, and one of them presented it to the son so that he might be able to marry. However, both the son and the father refused to take the money, claiming that if they took the money at that time it might be wasted. Instead, they asked the man to keep the money with him until the time that Allah wills the son to marry. The man deposited the money in Al-Rajihy Bank as he did not want to invest it considering that it was a trust. Since that time, the money has been in the bank for five years. Is Zakah due on this money? If so, who should pay the Zakah; the one entrusted with the money or the one to whom the money was given? (Part No. 9; Page No. 288) It is noteworthy to mention that the grantee has no money to pay the due Zakah. Also, the man entrusted with the money, who has deposited it in Al-Rajihy Bank, has been lending it out to the needy in short term non-interest loans that are repaid after one or two months, assuming that this will make up for the Zakah due on the money he has deposited in the bank. Is this lawful or not? Is the trustee sinful for doing this without asking permission from the father and his son (the owners of the money)? The man wants the father and his son to take this trust and wants to know how he can expiate for any sins he might have committed with regard to this money. May Allah reward you with the best!