Raines was continuing to receive care and treatment for his mental health.
He and his stepfather were known to clash, often over living arrangements as Raines was staying with the couple.
The night before the fatal shootings Raines was in a "negative or bad mood", his mum Janelle was quoted as saying.
However, there hadn't been anything significant to raise concerns or foreshadow what would unfold the following day.
On September 30, Raines walked past his mother holding a sawn-off rifle not long after she and Garry, 59, had returned home from running errands.
She asked what he was doing. Raines told her she didn't want to know or see.
A brief moment later Janelle heard her son call out to someone. Then came the sound of gunshots.
She rushed outside to discover her husband lying on the driveway of their Kamo home near where Raines was also lying - still alive.
Emergency services rushed Raines to Whangārei Hospital, where he died later that day. Garry was pronounced dead at the scene.
Herdson ruled the stepfather had died from multiple gunshot wounds to the chest, while Raines' wounds were self-inflicted.
Forensic tests revealed Raines had methamphetamine in his system alongside THC - the main psychoactive compound in cannabis.
However, Herdson was unable to make any findings as evidence of the amounts, source and time of use were unavailable.
She described the nearly four-year wait between the pair's deaths and the written decision as "regrettable".
"On behalf of the Coronial Services staff in Auckland I extend my sympathy to his family and friends for his death."
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youth services: (06) 3555 906
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• Helpline: 1737
If it is an emergency and you feel like you or someone else is at risk, call 111.
