"When my boy let me know that, he wasn't distressed about it, he wasn't sad or anything. He was actually oblivious to what had happened, really," Nepe said.
He said his first response was to advise his son to continue using te reo Māori.
"There is no harm in using two words, a two-word phrase, a common phrase. We know this, we know kia ora is the phrase from Aotearoa New Zealand."
A post he made to social media about the incident attracted a lot of attention.
Nepe said the manager in question had since transferred to a different site but took the initiative to apologise to his son on Sunday after seeing the post.
Nepe said the manager's comment was most likely innocent, as she herself is Māori.
"I truly believe there were no intentions of a racial attack on my boy or his language.
"In saying that, it is not OK that our boy and us as a whānau have to feel this way, of feeling discriminated against, of feeling it was a racial attack, despite the best intentions of the manager."
He said he had not been a victim of discrimination in Havelock North himself despite having a 'Mataora' male traditional facial tattoo and being a long-time resident.
"I feel very comfortable travelling down the streets of Havelock North with my Mataora and speaking to my wife or children in te reo Māori.
"Even though we've always put up with this kind of behaviour and attitude, we shouldn't have to anymore, whether it is a small situation or a huge situation."
He said he knew his post had huge outreach, but he wanted to make it clear that he didn't want anyone to express hate towards his son's workplace or the manager.
"I just want everyone to be treated with love, to be treated with respect and consideration. The intent of this post wasn't to get everyone protesting outside Havelock North McDonald's, this is about awareness. The safety of everyone that works there and the manager is paramount."
The McDonald's spokesman said the staff member in question was unable to identify for management the person who made the comments.
"Management spoke with other staff and reviewed CCTV, and it is still unclear who might've made the comment."
The spokesperson said McDonald's national position is to support the use of all three of New Zealand's official languages and they support the use of te reo Māori by staff and customers.
"We have bi-lingual signage in restaurants, celebrate Te Wiki o te reo Māori each year, and many crew who are confident to converse in te reo Māori wear pins supplied by Te Taura Whiri i te Teo Māori.
"The Hawke's Bay restaurants were at the forefront of encouraging the use of te reo Māori, including working with local iwi to introduce Māori language menus."