I took it to mean his words weren't about Memorial Day. His thoughts were more towards veterans, however Memorial Day prompted the internal musings, so he shared... And Hitman shared.
Fact is: for someone who isn't military but has had to deal with deployment, any pro-military holiday they are immediately going to think of their own. What matters is they get it. Deep down they recognize the truly important meaning. I wouldn't disagree with anything his dad said. Even about what it's about. Because in truth handling the fact he could have died is relative to this weekend and following Monday.
By the grace of God, his Memorial Day is far different than it could have been. D I think your dad was right on the money. No confusion at all about what Monday could have personally meant to your family. Something I think we all memorialize as a society until its one of yours. For many Monday is hell. Being slapped in the face all day every day this week, remember the fallen? Hell. There are no happy feel good bbq's or boastful claims of deceased great grandfathers.
For our current families, Monday is also a "what could have been". I think more than one parent will consider it. That's only natural human emotion.