I think we need more info on your Dad, if you really want our opinion.
He came here 53 years ago (legally), got drafted into the Army, served, married an American (my mother), and raised a family. Encouraged his two sons to become military officers (which they did). Worked hard, paid his taxes, and realized the American dream. He just never took the final step of citizenship. His choice. He doesn’t vote. He’s not allowed to vote. He SHOULDN’T be allowed to vote. And he doesn’t have a problem with it.
Yet some on this board would have him shipped back.
Word to the wise... not every immigrant slipped over the border in the middle of the night. Be careful you don’t tar them all with the same brush.