The death of Paul Walker was a blow to many people. His family, his colleagues, and his fans were all shocked by the loss. However, Walker's brothers say that Furious 7, actually went a long way to helping them deal with their brother being gone. Caleb and Cody Walker both helped stand-in for Paul in order to finish their sibling's performance in Furious 7. According to Caleb, doing this helped them get to know their brother better than they had before.
It had to be a somewhat strange experience to be pretending to play your own brother after he has passed away. Of course, walking in his footsteps can help you to understand somebody better. The brothers told ET that Paul never talked a lot about his work with the family. With Paul Walker being gone so often filming, and them not knowing much about what he was doing, certainly, being on the set would be an amazing experience. It would help them to truly understand what their brothers was doing when he wasn't at home. If that part of Paul's life had been a mystery to them before, then they would have learned a great deal by working with the people that he worked with so often.
The cast and crew of the Fast and Furious franchise were also a great help for the brothers to find some closure. Several of them, especially Vin Diesel, had some great stories about Paul that Cody and Caleb had never heard.
Paul Walker died unexpectedly in a car accident in November of 2013. In response, the ending to Furious 7 was changed in order to help write the character out of the series. Caleb and Cody Walker, combined with digital effects, were all used to recreate Paul Walker for the finale, allowing him to drive off into the sunset.
As much as Paul Walker was in the public eye due to the growing success of the Fast and Furious franchise, it would seem that he was such a private person in reality that there was a lot about him that even his own family didn't know.
While Paul Walker's family may have found closure, it doesn't mean that they're necessarily done his character. There has been some talk of bringing Walker's Fast and Furious character back at some point in the future. If that happens, the brothers will likely help reprise the role again.