What happens when you are reported for credit card default to CIBIL in India ?

My father is an old man of 70 years and is a heart patient. He had used a credit card and run up some bills and has taken ill thereafter. Even after explaining to the bank, the bank has sent a letter saying they will report him to CIBIL - the credit info buraeu. What does this mean ?|||my credit card all ready expired in india i am living in dubai now a am not able to coming that aountry