Writing to night shelter manager Annamarie Angus, she said having an alcoholic son had been a long and difficult journey, particularly because he did not believe he needed help.
By early this year he was financially ruined and facing eviction from his rented accommodation but despite his parents' efforts to get help, every door seemed shut.
She said Mental Health would not intervene because he was not deemed to be a risk to himself or others and the drug and alcohol helpline and Salvation Army were unable to intervene until her son admitted he had a problem and wanted help.
Things immediately improved when her son was dropped off at the night shelter, with staff putting together his CV to assist him to get a benefit from Work and Income.
She said the strict rules of no alcohol on site and that the men contributed to the chores had a positive effect.
The night shelter has been a godsend to John and to us as a family. Despite two years of trying to get help for John via other agencies, we continually ran into a blank wall.
"Since being at the shelter we have been able to let John [not his real name] see his daughters again. After four months of not seeing each other, the get-togethers have been very beneficial to all of them."
She said the night shelter's on-site social worker challenged her son to make better life choices and he had started to do charity work - helping to get him back into the world of self-responsibility.
"The night shelter has been a godsend to John and to us as a family. Despite two years of trying to get help for John via other agencies, we continually ran into a blank wall. Annamarie and her team do a wonderful job in offering support for people like John who because of their addictions fall through the cracks," she wrote.
Mr Mills said the night shelter had been the first ray of hope in their battle. "We are successful because we punch through the barriers."
He added that staff kept going until they got what was needed for clients. The man's case highlighted systemic issues to be addressed, he said.