The psychiatric patient was found half-submerged in a water drum his Tafa'igata prison cell in Samoa on Boxing Day 2012.
Samoan authorities refused to hand over official information to a New Zealand coronial inquiry, which couldn't determine how he died.
It's left Mr Dalton's whānau in limbo as they pursue legal action against the Samoan government over the 38-year-old's death.
Winston Peters met with Mr Dalton's whānau in September 2018, where Mr Dalton's mother, Christine Wilson, said she agreed to temporarily set aside the civil proceedings.
