First of all, the bank will contact the borrower by telephone, text message, letter, etc., urging him to repay the overdue money. If the borrower still fails to repay the loan or cannot be contacted, the bank will take further measures.

Secondly, banks may classify overdue funds as non-performing loans. Non-performing loans refer to loans that have been overdue for a certain period of time, and banks will include them in the list of non-performing loans to reflect the credit status of borrowers. This will have a negative impact on the borrower's credit record and may affect his future loan application.

In addition, banks also have the right to take legal measures to recover overdue payments. The bank can bring a lawsuit to the court, asking the borrower to repay the arrears and bear the corresponding liquidated damages and interest. If the borrower refuses to fulfill the repayment obligation, it may face the risk of property being sealed up, frozen or even auctioned, and may affect personal credit.

To sum up, the bank's measures to deal with the overdue mortgage for three months include collection, classifying the overdue funds as non-performing loans and taking legal measures to recover the arrears. The borrower should properly handle the overdue situation in time to avoid causing greater damage to personal credit and financial status.

The above answers are based on the general situation, and the specific handling methods may be different due to bank policies, loan contracts and local laws and regulations. It is suggested that the borrower communicate with the bank in time in case of overdue, and abide by the contract, so as not to further aggravate the debt pressure.