Not what it seems
Good one, you had me for about 10 minutes.
A response to the collection of words is not the answer since these sentences are not questions, but rather each individual sentence is a statement which stands alone, containing the word which is being described.
What has 4 letters.
The word WHAT is made up of 4 letters.
Always has 6 letters.
The word Always is made up of 6 letters.
Never has 5 letters.
The word NEVER is made up of 5 letters.
And sometimes has 9 letters.
The word SOMETIMES is made up of 9 letters.
Edit, you beat me to it, since I took so long to type my response out.