Is purchasing a car or electrical appliances in installments through the bank, where the bank pays the seller and the buyer repays the bank with a specified increase, considered usurious?

If the bank pays the remaining price of the car to the dealership and then collects it from the buyer in installments with an increase, this is usury (riba) and is not permissible, because the bank has lent to the buyer and taken interest on the loan. It is not permissible to deal with the bank in this manner. Instead, the Shariah controls for Tawarruq (monetization) or Murabahah (cost-plus financing) must be observed. Your brother is not permitted to start a private project based on this forbidden transaction, as Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty" (Al-Ma'idah: 2).