"I'm very relieved and thankful and that they're together and one isn't left behind," said Renae Meyer.
Robert and Elizabeth Rotta were going to dinner with their son after an early Mother's Day celebration when police say the bus ran a red light near the I-405 transit ramp and crashed into the passenger side of the Rotta's SUV.
Robert Rotta, a retired Boeing worker, died at the scene and Elizabeth Rotta, a former missionary, died later at Harborview Medical Center. Their son Ken, who was driving, suffered a broken rib and was also sent to Harborview. Troopers say one person on the bus suffered multiple but minor injuries.
Meyer said Harborview doctors kept her mother alive long enough so family members could say a final goodbye.
"They wheeled (Ken) in and put the two beds next to each other so they could talk to each other," said Phil Rotta, the couple's son. "Some of the last words: 'Be sure to say hi to (Dad) from us.' "
Troopers spent Tuesday examining the 2008 Sound Transit bus, still trying to pinpoint what went wrong and who might be to blame. The bus driver, Alexsandr Rukhlin, told investigators the brakes failed. Investigators say he showed no signs of being under the influence.
"Our focus at this point is driver error, potential vehicle issues, anything else in the roadway," said Washington State Patrol Trooper Julie Judson.
Troopers still need to test the vehicle, see if the brakes are faulty, and won't release safety records until that's done. The driver has no criminal history in Washington; his employer says he's been there almost a year with no problems.
Rukhlin's daughter said he's distraught, had spent years driving trucks in Ukraine and would never hurt anyone.
But Rotta's family members say the were not concerned about whether the bus was faulty.
"I believe in providence and I believe that whether someone is hit by a big Mac truck or hit by lightning, it's by the hand of God," Meyer said. "And I think just the timing of this accident was so precise. If they were 15 seconds earlier or 15 seconds slower it would've been a different story.
"I just believe our days are numbered and it was just their time."
Ken Rotta, a pilot for American Airlines, could be released from the hospital as early as Tuesday night. Rukhlin has been suspended until the investigation is over.
Robert and Elizabeth are survived by three children and 13 grandchildren.
"I think both my parents have laid a very important legacy and it's going to be something that we can follow and our kids and grandkids can follow," Phil Rotta said.