Raden Andante Khalif Pramudityo or Dante passed away because he was intentionally drowned by Yudha Arfandi or YA in the swimming pool. Yudha Arfandi is the lover of Dante's mother, Tamara Tyasmara.
The death of Dante certainly devastated his biological father, Angger Dimas. Angger Dimas revealed that Dante had previously said he didn't like swimming activities.