Cleveland Cavaliers star Kevin Love -- one of the NBA's most outspoken proponents of mental health -- is mourning the loss of Stephen "tWitch" Boss on Wednesday ... and is urging people to reach out to their loved ones and to spread kindness to prevent future tragedies.
Love took to Instagram to send his condolences to the famed Ellen DeGeneres talk show DJ ... sharing a photo of Boss with an emotional message.
"Everyone is going through something that you can't see," Love wrote on the social media post.