He is 5.
When he says things like this, he is not being literal about it.
It is just a phrase.
Trying to make HIS response, different, may not work.
Because this is a phase.
Kids.... go through many developmental phases, of which their emotions and words and wording are just that. They are 5. Then when older of course they develop more.
I have a son that is 5. And yes, my son is VERY verbal AND has many words and emphatic expressions that he uses. But so what. It is no biggie. I know he is merely stretching his wings verbally and in how he CONVEYS things. Which is not to be taken literally. But for a 5 year old, they naturally have a sense of pretend play and opposite words.
To me, it is an exercise in their development of language attainment and usage and development.
He is not trying to be accurate or exact or literal. He knows that.
He is 5.
I think this is a matter of personal preference.
He is not 10. But 5.
He will not go to school, or continue in school and be always saying this throughout elementary school.
It is a for now, phase.
You want your son to choose his words "correctly and better," and to be more "accurate." But for him, he IS expressing himself about situations. That is how he "feels." For him, it is not about choosing the best word from a dictionary to suit others.
He is 5. He will learn tons of other words.
Given the situation in which your son says "Never," he is expressing what HE feels IS relaying how he feels. Not a literal sense of the word. It is fiction.
I know some ADULTS who use the word "always" or "Never" a lot as well. ie: "You never listen to me...." "Why do you always leave your clothes on the floor." "You never do your school work well." "Why are you always late in getting home after work?" "How come you never listen to me?"(for a wife talking to a Husband.), "You never do your chores." "You never eat what I make." etc.
Some people are very boxed in by vocabulary. Some are not.
Some people are very literal. Some are not.
For example: if I tell my Husband that I'm tired today. He actually thinks, I feel so tired. Meaning, sleepy. But it is just an expression, about my day. Then he will ARGUE with me about how I should NOT have used the word "tired" but rather another word, because to HIM, being tired means the person should just go to bed. So if I tell him I am "tired" his next response is "Then go to bed instead of saying it." But he is not interpreting me, correctly
Now, if he tried to get me to choose another word to suit HIM, as I talk, well I would just go talk to someone else. I express myself, being myself. I am not him. He is not me.
So, the next time I just want to say I had a hell of a day and am tired and numb from the activity of the day.... he may take it literally.
But to me (since I am the one that said it) and to many other Moms, they know that I am just expressing how the day went. It is not LITERALLY that I went to Hell and am tired and will sleep and that I am actually numb because of the activity of the day.
I think this is what Authors must go through.
Its a matter of interpretation as well.
And it is a phase.
No biggie.