Mr Horan, who has always denied the allegations, stayed in Parliament but failed in a bid to become an independent MP at the last election.
It emerged later Mr Peters had been passed information by Mr Horan's half-brothers, who were behind a number of new versions of the will which inflated their share and were written in the months before their mother, Olwen Horan, died.
A video also emerged, showing the late Mrs Horan objecting to changes made by Mr Horan's half-brothers.
Miranda Horan said the accusations had made the family - including their two children - closer through adversity and had also revealed "close friends" from those who treated him as a pariah.
"We know what Nana was like - she did what she damned well pleased with her money. There was no way Brendan could have taken anything from her because she wouldn't have allowed it.
"I'm really stoked for Brendan. He's not going to get his career back but I hope it goes some way towards restoring his reputation. He has handled this with grace and dignity," she said.
He's not going to get his career back but I hope it goes some way towards restoring his reputation.
Mr Horan said the police investigation has dogged him and made it difficult to secure sought-after jobs.
"I always knew that would be the result but it's a long time and it's certainly taken its toll in regards my reputation and the livelihood of my family.
"It's very difficult to get employment with my skill sets going through police checks when they say there's still a police investigation open."
One job sought by Mr Horan was a public posting for which he applied supported by a minister and senior public servant. Neither referee was called and he wasn't asked to interview for the posting.
"That's the consequence of having your reputation trashed."
Asked about Mr Peters, he said: "I'd rather not talk about that man. I'm finding it difficult to forgive myself for believing in him."
Mr Horan considered his time in Parliament well spent, having been active as a local MP working for the people of Tauranga and as having influence on legislation passed in the House. Among that was the casting vote on the legislation which "Mondayised" Anzac Day and Waitangi Day.
He had stayed involved in politics as junior vice-president of the former MPs association.
Mr Peters said he had made the right decision in kicking Mr Horan out of NZ First.
"As a leader I have to make a judgment. If I'm going to back someone, I need some answers. When I put it to him, no answer was satisfactory."
Mr Peters said he was responding to the line in Mrs Horan's will - the final version - which asked for an investigation into spending.
Bay of Plenty criminal investigations manager Detective Inspector Mark Loper said the investigation into the allegations, made by Mr Peters, had been "comprehensive" and had been reviewed by senior detectives.
"After consideration of all relevant information and the Solicitor General's prosecution guidelines, police have determined that there is insufficient evidence to charge any person with a criminal offence."