Why on earth would you fake amnesia? Why didn’t he have family or friends to take care of him? Or a neighbor??? Why move in with your boss?? In what world is that the best option? It also made the 3rd act break up too predictable and idiotic. It did have some nice bits hence the 2.5. 

If you do wanna read this: the audiobook is hard to follow due to the scouse (i think?) accent.