Scott, my husband lost 9 friends in 18 months when he was younger due to road bike accidents and car accidents. He still rides road, he still drives. He decided after everything that life is just too short, so make the most of the time you have.
I lost a few friends due to road bike accidents when I was younger, too. One was the most difficult time I've ever had. Erin died on the way to work, he didn't see a truck had stopped & went straight under it - closed casket due to decapitation. Another was a friend who'd asked my then b/f & I to go with him on a ride, but we couldn't make it. He overtook another in the group, clipped the back wheel & landed on his neck. An off-duty ambulance officer was in a car behind them & saw the whole thing - there was nothing to be done for Brett. Another friend (well, of my sister) broke down so phoned her husband to fix the car. Steve came out on his bike & after they both got going, a drunk driver (this is 7am, Kathryn on her way to work), clipped Steve's bike & he also landed on his neck - the tragic thing about that was Kathryn was behind him & saw it all & could do nothing.
I've not lost a friend due to riding off road, but I've lost good friends and it's hard.
One story that may or may not help. A top New Zealand rally driver (you may have heard of him - Possum Bourne) was at a rally a while back & they had an accident & his navigator died. He then had to stop & think about it. He continued on driving because he didn't want his navigator to have died in vain. Possum died earlier this year & our country went into mourning, but he died doing what he loved and he gave us brilliant memories.
I'm truly sorry to hear about your and Dave's friend and it is now your decision what to do. One word of advice though - don't sell everything yet if you decide not to continue, once the painful mourning period passes, you may change your mind.
Condolences to all of your group & Darryl's family, it's never a good thing to hear :(