A report says a rehab centre took a client's benefit money, failed to provide alcohol treatment, encouraged him to stop taking his medication and allowed him access to knives and air rifles.
The man, who also suffered from depression, checked into the facilty in July 2012 and was evicted four months later after he argued with the director.
The Health and Disability Commissioner has not named the facility, which is staffed by the director, his wife and a part-time unpaid counsellor.
It found that once the man had paid for his board, food and counselling, he was left with $7 a week.
His counsellor arranged for him to do extra work at his church but paid the man less than he was charging for his services.
The report found the counsellor failed to provide counselling or a treatment plan and kept no clinical records.
It has referred the counsellor to the Independent Director of Proceedings.