Professor Nemur was one of the scientists in charge of the experiment. He would probably would have been very impersonal if he were narrating the book. He would have seen the pre-surgery Charlie as inhuman, and would probably have talked about how he had basically created Charlie.
If Alice Kinnian, Charlie’s teacher before his surgery, had been telling the story, she would probably have noted the changes in Charlie’s personality as he got more intelligent, and also talked about how she was falling in love with him. She probably would said how she felt distant from Charlie after he became smarter than her. As Charlie began to regress, she might have written how she had mixed feelings; she was sad that Charlie was becoming retarded again, but at the same time wanted to have Charlie at her own level again, even if for only a short time.
If the people from the bakery had been telling Flowers For Algernon, then they would have written about how Charlie had gone from being retarded to being a genius in just a few weeks. They hadn’t been told about the surgery. They probably would have said how they thought something really weird was going on.
If someone else had been narrating Flowers for Algernon, the story could have been very different. For instance, Charlie saw Professor Nemur as arrogant, but if Nemur had been keeping the journal, then we might think of Charlie as the stuck-up one. In other words, point of view has a very big part in this story.