I think we have well and truly lost Minkowski
Just like poor little Eloise, he suffered a brain arumetism (don't know how to spell it), as the constant conscious time switches caused his brain to implode. Obviously it lasted longer than Eloise due to brain size and capacity but everything has it's limits. Minkowski I'm afraid is dead
However I do believe that there is a strong possibility of George coming back in spirit form. As everybody who dies within the vacinity of the Island Bubble has a chance of doing, the dead may very well rise.