Former UC Berkeley graduate student Jose Lumbreras was sentenced to six years in prison on Tuesday for the vehicular manslaughter of his 22-year-old girlfriend, Milanca Lopez, and her 6-year-old son, Xavier Chevez.

Lumbreras was charged with two counts of gross vehicular manslaughter while intoxicated, resulting in a six-year sentence with the possibility of being released in two years after receiving credit for time served, according to Lumbreras’ legal defense.

Members of the Lopez family were pushing for the maximum penalty in this case, which would have resulted in a a 12-year prison sentence for Lumbreras.

Paul Wolf, Lumbreras’ defense attorney, appealed for a lighter sentence during the hearing on June 11, arguing for probation instead.

“No amount of sentenced time could bring back Xavier and Milanca, and that’s the tragedy,” said Richard L. Richardson, an attorney representing the Lopez family.

Lopez and her son were killed in a drunk driving incident in May 2012 in which Lumbreras was the driver. Lumbreras, who was operating the vehicle on a residential street while intoxicated, collided with a tree near California Street and Allston Way. At the time of the accident, Lumbreras had a blood alcohol level of 0.16 — twice the legal limit.

Lumbreras pleaded no contest to both counts of gross vehicular manslaughter while intoxicated.

“In my 37 years of practice, I never defended someone with as many achievements,” Wolf said. “Jose is a man of unknown potential. This is the most tragic case I’ve ever been involved in.”

Lopez’s parents also filed a lawsuit in May against Lumbreras, the UC Board of Regents and a UC Berkeley housing employee, claiming the university failed to respond to alleged reports of Lumbreras physical, verbal and sexual abuse of Lopez.

Lopez’s family claims the alleged abuse took place at University Village, a campus family housing unit where Lopez and her son Xavier lived. The allegations brought up in the lawsuit have not been verified.