Today was my day off!

I still can't believe that this happened. At 9:15 I heard something falling, and i knew that this was what happened. It made a Lego specific sound. I came into my son's room, praying it was not what i thought it was, but unfortunately it was even worse. My son is a Lego and Star wars fan. He is really good at building, so i only help him insert technics type parts, because he doesn't have the strength for some of them yet. He has built many 18+ sets on his own, and he spends all the money gifted to him on Lego, he only wants Legos for his birthdays. So he has a huge collection for a 6 year old. Yesterday around 21:00 he finally finished his masterpiece, Death Star. He has been struggling with it for weeks, because this set is somehow delicate, many times broken some stuff while putting on new parts, so it took more than i would ever spend time on anything. But still, he made it, and we put it on a wall shelf in his room. After i put it on the shelf, my wife told me that the shelf looked like it was crooked, or bent because of weight. I didn't see anything wrong, so told her the shelf had a capacity of 100kgs, and nothing will happen. And it happened, taking down other big, star wars Lego sets he built, and leaving a huge pile of Lego mass. I will have to rebuild them all. and i will most probably have to spend days doing it. If anyone has any suggestions, or tips, you are more than welcome.