If the person suffering from the illness mentioned in the question knows the ruling and meaning of talaq while pronouncing it then talaq shall take place if he gives divorce to his wife with the word of talaq. However, if due to the illness, he does not know what he says and the ruling which is applicable on it then in this case talaq shall not take place on his wife. [From: Fatawa Mahmoodiya Vol. 12, p. 298]
Note: – What is the other word which he uses except of the word talaq? Write it and submit your query again, then in-shaAllah, we shall reply you.
Allah knows Best!
Darul Uloom Deoband