So

No, but the series tried to blame it on the cookies he ate.

Wtf that's like so borderlined
There's no context and all
They are like we want this scene so let's deviate story here
Then we want this scene then deviate here
And no middleground in doing so

So he isn't insane?? Is he just pretending??

The novel had a lot better context. Chinese comics, or comics in get adapted from novels in general (but heavily in Chinese) tend to skip details and extra explaining if it can, probably due to saving a few drawing panels which reasonably saves hours of work. I've noticed this especially strongly in Chinese novels though, were they accidentally and frequently delete important context clues that makes comic readers only confused

But he is pretending??