The person appointed as Personal Representative and issues Letter Testamentary if there is no other way to get the medical records. Because of HIPAA, people are concerned about releasing medical records even after a person's death.
The information provided in this answer does not create an attorney-client relationship and is not considered to be legal advice.
Unfortunately, there isn't an easy answer to your question. Medical record release policies vary from facility to facility. There is nothing in the law requiring medical facilities to release medical records to immediate family members. In fact, quite the opposite. I have had situations in litigation where people were unable to get medical records of deceased spouse's without first getting appointed as the deceased's personal representative by a court. If the hospital won't release the records, you may need to speak with a probate attorney about opening an estate for your dad. It's a pain, but medical records do often contain the most personal information about us that there is.