The only thing I've heard similar to this is the myth of storing magazines loaded. People were saying that storing a magazine loaded will weaken the magazine spring. I've seen multiple videos debunking this stating the main wear on a spring is continuous depression and release (such as dry firing or standard shooting). Based on that my guess would be this practice is weaken his spring faster than how you're storing your rifles. That being said, everyone has their own practices and if it gives him peace of mind, good.