The family released an initial statement following the news, and described him as "a bright light in this world for his family, friends, and fans. Thank you for your prayers. Please respect our privacy. There are no further details as to the cause of his death at this time."
But no words were necessary in his mother's latest post, which features a broken heart emoji and a photo of Miller and Meyers smiling together at a baseball game.
In the comments, fans are sending messages of support.
"I can not begin to imagine your pain," one wrote.
Ariana Grande, who dated Miller for almost two years, posted a similarly poignant tribute, declining to caption a photo of Miller, and turning off comments on her Instagram.
The cause of Miller's death is still unconfirmed. His loss is felt across the industry and beyond.