Every loan paid for gaining a benefit

Q: One of my coworkers needed an amount of 400,000 riyals to finish his building after work had stopped for two years. He asked me to give him the 400,000 riyals as a loan to finish his building and told me he would give me in return the right to benefit from three out of the six apartments in it. They would be totally mine whether to rent out or live in until he had paid off the entire amount in cash.We asked some Shaykhs about this agreement and they said it was permissible. They said the profit of the three apartments is not a definite amount and the repayment period is not fixed as well, as it may extend from two to four years. Based on that, I withdrew the said amount from the Islamic bank I deal with and which gives me interest. Later, other Shaykhs told us that this transaction is not permissible and now I am confused. Appreciate your guidance, may Allah guide you.Is taking the profits or rentals of the three apartments in addition to the original loan lawful? Bear in mind that my coworker is well-off and has a ten-apartment building other than this building. His monthly salary is more than 10,000 riyals. If I refuse to take the profits of the three apartments, I will lose since I withdrew my money from the Islamic bank (Part No. 14; Page No. 123) and will not be receiving interest for a long time while he is making use of my money and he is not in dire need of it. If taking the rentals is unlawful, can I give them in charity? May Allah grant you success.

A: It is not permissible to lend your coworker money in return for benefiting from three apartments by leasing or living in them until he pays off the loan, as this loan is paid to gain interest. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.