Alex,
I like the puzzle you set up and I bet that you have had long conversations with your brother during the painting process.
I like the many mirror images in the windows that could inspire to reflections about a persons life.
When you are young you want to grow up and get into something, and when that happens you may look into the mirror of your soul and want to be young again, because you might want to do things otherwise and so on.
It's a great painting and more complex than I like to think of.
Thank you for showing it.