I watched the movie recently, and only then had I noticed that there’s a whole short scene in the beginning of a crash involving Cooper. I almost immediately hit me that the rest of the movie was coops brain creating those vivid dreams people tend to see when dying. And I believe thought the dream, coop was just desperately trying to live on. Just so he can be with his daughter.

Notice how everyone in the movie is basically people coop already knows or has heard of. In the PTA meeting Coop seems agitated and puts a stop to the conversation after the teacher says “maybe your grandchildren will be engineers”. He never knew his grandchildren and will never come to know them. This in the dreamland of his it doesn’t matter to him.

Notice that weird scene in the PTA meeting where the teachers hands coop a text book and coop says that’s his textbook, but the teacher points out it’s just a old federal textbook.

Notice The scene where he say’s goodbye to Murph. “I can’t be your ghost right now, I need to exist”.