How sound is the statement that the birth of the intellect occurs after the birth of the human, and the death of the intellect occurs before the death of the human?

We believe that what is meant by "intellect" in this phrase is understanding and the acquisition of knowledge. The first part of it is clear, while the second part is not entirely so; some people retain their intellect until death, while others lose their intellect before death. These are those who are "returned to the worst of life," where a person reverts to a state similar to childhood in terms of weakness of intellect, understanding, and the loss of perception.