I think you 'll have an idea when it is time to return home. At some point the family will have to transition to a time of more "normalcy", going back to work, deciding if they can still live in the house. I still wake up every day with a heavy weight on my chest. It's not that I can't enjoy anything; it's the weight (and aging) of terrible loss. The place where Jim ran into oncoming traffic is a place I must drive past every single day. Some days I don't process it; others it grabs me and I can't breathe.
In the meantime, would your kids come join you for a weekend and spend some more time with cousins? Might be healing for all.