credit card comparison

Okay, morbid thinking. My parents have life insurance but from what I know they just have joint bank accounts. So if Dad died and Mom wanted to refinance the house or something, would she be able to do that or does the 20+ years of excellent credit count for nothing because Dad was/is the primary card holder with Mom as the authorized user which I believe is the arrangement.

Would Dad’s dead credit be excellent and Mom’s at virtually nothing by comparison or would the good credit card payments be reported on Mom’s report as well?