Is it considered deceit for a brother to register himself as an employee with a friend, even though he is not working, in order to fulfill the seller's condition for purchasing an apartment in installments?

The seller has the right to stipulate conditions to the buyer that guarantee his right to the price of the commodity, and the buyer must fulfill this condition if he accepts it. It is not permissible for the buyer to breach the condition, or to deceive the seller and mislead him with something contrary to the truth. Rather, he must be frank with the seller about his true ability to purchase. If the seller agrees, then so be it. Otherwise, the buyer should look for another seller who does not stipulate this condition.