"As a family you find it hard to breath sometimes."
The former Boyzone singer said he was "floored" and "disappointed" by the sentencing, describing the judicial system as "broken".
"We don't want to see some kid go to jail, whose life is going to be thrown away, we don't want that, that's not what we're looking for," he added.
"But what we're looking for is to make sure somebody else doesn't die because of carelessness. That someone else's family is not ripped apart.
"Is our judicial system here in Ireland that broken? It's ridiculous. Ciaran's memory will not be brushed under the carpet because of that."
Keating said he has not seen any movement to change the system since the sentencing earlier this year, so his family are taking action.
"We won't let this lie. We've looked at other cases, other families that have gone through what we're going through - some more recent (than ours). It's continuing to happen. Something needs to change," he added.
Ciarán Keating's wife Annemarie was also seriously injured in the crash and she now has severe PTSD (post-traumatic stress disorder) and survivor's guilt, her son Conall told RTÉ.
Earlier this year, the court heard how Harte failed to take a bend on a stretch of the N5 between Swinford and Bohola.
Harte's Audi A3 crashed headlong into Mr Keating's Ford Focus and the 57-year-old died at the scene.
The court was told nobody was speeding during the incident.
