He died in the intensive care unit at Wellington Hospital on April 16.
An inquest is being held this week before Coroner Janet Anderson.
"We can no longer help Henry but changes can be made," Henry's mother Philipa Kitchin said in a powerful statement made to the court on Monday.
She said she hopes the Coroner's eventual findings may be able to save other young people from harm as a result of their mental health.
At the time of his death Henry was receiving mental health care from Capital and Coast District Health Board Mental Health Services. He was experiencing suicidal ideations and felt unsafe at home.
This care was provided via the Mental Health, Addictions and Intellectual Disability Service for Wairarapa, Hutt Valley and Capital and Coast District Health Boards known as MHAIDS.
Kitchin later said while giving evidence to the court that it was "devastating to know that he was let down by the professionals and the institution that was supposed to help him".
Kitchin said her son "was a lovely little boy who had a happy childhood", but several factors impacted his psychological well-being.
Bullying, family life, and struggles at school impacted Henry from a young age, leading to what was described as "feelings of low self esteem and worthlessness".
When he started school at Wellington High School in 2011, he had already faced mental health interventions, and in 2012 was prescribed medication for his "low moods".
By 2014 Henry had made friends at WHS, was writing a script for a movie he wanted to make and had a steady girlfriend.
A health practitioner who examined Henry's mental health in 2014 said he didn't appear to be "remarkably depressed", however his mental health took a steep decline as his depression worsened.
"His depression was sometimes so bad he couldn't get himself out of bed," Kitchin said when giving evidence to the court.
He was referred to a number of community mental health organisations and seen by doctors. His self harm escalated, at one point gouging the skin on his hand after a mental breakdown.
Kitchin said her son expressed feeling "unsafe" one day in July 2014, and she feared he would hurt himself.
By the end of the year Henry was expressing suicidal ideations and his depression was described as severe.
In the lead up to the evening of April 14, 2015, Henry's medication had increased significantly.
His mum believes if he received treatment by speaking with a psychologist, rather than prevention through upping his medication, things may have been different that day.
"Every time he had a crisis his medication was increased," Kitchin said. After each dosage increase of Fluoxitine, Henry was described to be "zombie like" but when his medication escalated, thoughts of harming himself began.
"Had no motivation to do anything... he would just lay in bed all day."
When Henry was admitted into the community respite facility on 11 April, he again felt "unsafe at home".
Kitchin didn't know that there was a more secure facility for teens at Wellington Hospital, and said she would have chosen for her son to be there instead of the facility where he was found unresponsive days later.
Two workers from the respite centre told the hearing that the facility was understaffed that evening, an occurrence not uncommon in the mental health sector.
Henry's case manager, who has been granted name suppression, said she was told to be checking in on him every 30 minutes, a schedule recommended by a clinical physician and out of the facilities control.
The support worker spoke about the night Henry was found in his room. He was quiet as she checked in on him every 30 minutes.
She said in her final check at 6.45pm that evening she had a feeling something was wrong.
Another worker who held a more senior position and had been working through the number of merges to the centre for over 20 years acknowledged the fact his team were understaffed that day.
He said the respite centre was a place for young people to have space under supervision, but that changes to the frequency of checks couldn't be made by the workers at the centre.
Coroner Anderson asked both witnesses what changes could be made to prevent harm, and both spoke candidly about resourcing issues including staffing and financial aid.
"Resourcing and money... most of that would be around increased staffing particularly in counsellors and therapists, a vast number of young people aren't receiving talking therapy," she said.
"I think there is a huge workload and there is a huge need for talking therapy."
The inquest continues today.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633 or text 234 (available 24/7)
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (12pm to 11pm)
• Depression helpline: 0800 111 757 or text 4202 (available 24/7)
• Anxiety helpline: 0800 269 4389 (0800 ANXIETY) (available 24/7)
• Rainbow Youth: (09) 376 4155
If it is an emergency and you feel like you or someone else is at risk, call 111.
