Consesco Washington National Insurance Improper Documentation of Insured information Carmel, Indiana

My father was solicited for cancer insurance with this company many years ago when he owned a small grocery store. When he was sick approximately 10 years ago, they managed to send a check. Unfortunately now, when we have attempted to file a claim again, suddenly his birth date is incorrect and they are refusing to use any other type of identification to ensure it is his account. If they paid once before with him using the correct date, then why now the date is incorrect? he is 92 years old now.