Jojo John was piloting the powerboat when it hit a stationary barge involved in the construction of the new bridge, killing bride-to-be Lindsey Stewart and her fiance's best man Mark Lennon.
They were thrown from the boat and drowned on July 26.
The 35-year-old John and his surviving passengers argued that the barge was not lit and impossible to see.
The district attorney said John had nearly double the legal amount of alcohol and traces of cocaine in his system.
John admitted he'd been drinking all day prior to the crash.
He is expected to be sentenced to one year in prison for each death, to be served consecutively in local jail.
In response, Jeannine Lennon released this statement:
"The Lennon & Stewart families believe that Jo Jo John's lenient/reduced sentence is a direct result of the evidence against the barge company which has escaped justice unscathed. We are extremely saddened to know that even though the Rockland County district attorney's office has evidence which proves that the barge companies are at fault because they ignored warnings that due to inadequate lighting this was an accident waiting to happen, it chose to ignore such evidence while only holding one party accountable for their actions."