Not dead. At the end of X-Men 3, that is, after the cast list is finished, there is a hidden plot involving the brainless man and his nurse. The nurse came to greet the brainless man. The brainless man answered her, and she called out Charles' name in surprise, which was the professor.
The professor showed a short video during a previous class. In the film, a female doctor was taking care of a vegetative person. Then the professor said that the vegetative person had no brain consciousness. Before his death, the professor used his powerful mental power to transfer his consciousness to the brainless man, completing a rebirth in a sense.
Extended information
Plot introduction:
The death of Jean (played by Famke Janssen) has had a lasting impact on the X-Men , Scott and Wolverine Logan (played by Hugh Jackman) suddenly seemed lost. The teaching task of the college falls on the shoulders of Storm (Halle Berry) and Wolverine. Only here can aliens get their identities recognized.
A company extracted the "antidote" for the mutated X gene from the genes of a mutant child, which can make the mutant's body the same as that of ordinary people. caused a strong response.
Magneto (played by Ian McKellen) contacts aliens who are unwilling to change their physiques, trying to use violence to resist unfair treatment in human society. Wolverine and others discovered that Jean was not dead, and that her awakened second personality was extremely powerful.
Professor X (played by Patrick Stewart) and Magneto each fight for Qin, and she becomes a key figure in changing the world of aliens.