YOU SAID:

I was nice to him just because he was

INTO JAPANESE

彼がいたからといって私は彼に親切でした

BACK INTO ENGLISH

I was kind to him just because he was there

INTO JAPANESE

私は彼がそこにいたからといって親切でした

BACK INTO ENGLISH

I was kind because he was there

INTO JAPANESE

彼がいたので親切でした

BACK INTO ENGLISH

I was kind because he was there