YOU SAID:

he wants to not feel so good

INTO JAPANESE

彼はとても気分が良くないと思っている

BACK INTO ENGLISH

He thinks he is not feeling very well

INTO JAPANESE

彼は気分がよくないと思う

BACK INTO ENGLISH

I think he is not feeling well

INTO JAPANESE

彼は気分が良くないと思う

BACK INTO ENGLISH

I think he is not feeling well