Young couple goes on van tour of US, boy comes back with van - no girl

I’m lucky that I’m not in a position to know, but what is ‘find closure’?
Is it possible with a tragic loss
I can’t remember how long ago MBS lost his brother, but I think it’s been awhile and it still seems raw
My wife’s family lost her father to a motorcycle accident decades ago, and the loss seems to have encoded itself into my MiL’s life
I’m not trying to be obtuse, but what is closure?
I think the closure is in knowing that the person responsible for this whole mess actually did this and he's offed himself or faced justice. They no longer have to wait for justice.

That certainly doesn't mean the pain and grief goes away.