YOU SAID:

His head then got smashed into the sink causing brain damage

INTO JAPANESE

彼の頭はシンクにぶつかり、脳に損傷を与えました

BACK INTO ENGLISH

His head hit the sink and damaged his brain

INTO JAPANESE

彼の頭は流しにぶつかり、脳を傷つけた

BACK INTO ENGLISH

His head hit the sink and hurt his brain

INTO JAPANESE

彼の頭が流しにぶつかり、脳を傷つけた

BACK INTO ENGLISH

His head hit the sink and hurt his brain