Talking to the Herald on Sunday, Shepherd said he was devastated about the events but was grateful that his son was recovering.
"I'm happy that he's all right," he said, adding that his boy's scars were now healing.
Mea was not at kindergarten, but was recovering at his mother Katarina Kopa's house most of the time.
Shepherd now faces possible eviction for keeping a dog on the HNZ property without permission.
Shepherd said he was still waiting on details from HNZ, but was despondent at the thought of being evicted.
Within hours of the mauling, Housing Minister Nick Smith promised to investigate the attack.
This week a spokeswoman for Smith said: "Housing New Zealand will be following ... policy to identify its next steps with the tenant. However, it is appropriate to give the tenant time to focus on his son's recovery and as such, no decision on these next steps has been made at this time."
The dog attack sparked renewed debate about a ban on some dog breeds.
Shepherd said the incident had changed his own view on pitbull terriers which he believed should be banned. "I don't trust those dogs," he said.