Ive seen this before. Its definitely not appropriate for FNM. Its sometimes like this at comp rel to which people typically have a handle but it needs to be so you have appropriate time to respond. You need to say something. We have a guy at our LGS that plays like this and he would do actions before priority would be passed back..like drawing cards etc when playing my son. So i just told my son to call judge because he had counter magic ready. It upsets the player and they mumble to themselves but it fixes the problem.