My father is older and nearing the time that he will probably soon die. He never really learned the gospel but was actually baptised and even went to the temple. As I have been taking care of him, I have had the missionaries visit him but have now learned sins that he has committed that have hurt our family deeply and has no regret regarding them. Most are sexual in nature. Do I keep trying or just let the eternities take care of it?
How difficult this must have been, and currently, to be awakened to past sins that have caused you and your family so much hurt.
In the gospel of Jesus Christ it is our responsibility to warn, expound, teach, and share the gospel and its principles. One of these doctrines is the correct understanding of repentance — to confess and forsake — as well as to feel godly sorrow for our offense toward others and toward God.
Once we have done our part, then we leave matters in the Lord’s hands. At times we may have a righteous desire, and then we become over zealous in our personal expectation. Once he has been taught, we allow the spirit of the Lord to work on him, and allow the spirit to be the teacher.
I would recommend inviting the missionaries over. Allow them to teach the doctrines of faith and repentance. If your father still is unrepentant of series transgressions (sexual sins), then leave the matter with the Lord.
There is no need for you to feel less of a person because you have not been able to help him see the light, and the error in his past decisions.