If you have social security, just copy the passbook of the social security issuing bank. If not, you can go to the retirement pension issuing unit to issue a certificate and copy the relevant account number or bank statement.

Generally speaking, the loan period can only be five years after retirement, which depends on the relevant regulations of the bank.

In fact, generally speaking, your income is higher, slightly higher. You are the main lender, and the house is shared by your parents. Your parents' pension income will be properly considered, and the bank will also lend money.