im not perfect enough to preach or make judgements regarding what others have done as to some degree I have made poor choices at one time or another that effect other people.
What would you rather your father do, realise that he has made a mistake and do nothing about it or not be bothered about the past.

He's possibly attempting to right past wrongs and listening to this man, and expressing your feelings is not a bad thing imho and changes nothing... He's your dad when he starts acting like it, when he deserves that title and only you can decide when that is, if at all.

Presently hes a man who appears to be trying to correct his mistakes for whatever reason, is that so terrible ?... we all make mistakes in life