You might be surprised if you knew how many people have been carrying an idea along with them throughout their lives. They get frustrated because they have thousands of hours of thought invested into something and when they attempt to talk about it they are usually talking to someone who hasn’t given it any thought at all and they are thinking on the fly. I can relate to your brother in some respects because I have done the same thing with the concept of collaboration starting in my early 20’s. Every couple of years I will delete hundreds of pages of work in an attempt to erase it from my mind but it just keeps coming back. It is impossible to talk about because no one else has given it that much thought.