I do not think many parents actively search. Winnie Johnson was a bit different because she knew who had killed her child, and the area where he was buried so had somewhere to make a start. Poor lady she had the worst of both worlds really, although she at least knew what had happened to her child, she had all hope removed, and had every parent's worst nightmare confirmed, and she never got the closure, as it were, of being able to find her child and give him a proper burial. She died knowing her was out there on the moors alone.
As for other parents, I do not think any two families react in the same way, it is such a personal thing. I think some families convince themselves there loved one is still alive, whereas other belive they have died. I know katrice Lee Major's family believe she is still alive, whereas Suzy Lamplugh (who was in her twenties though, but a child is still a child to the parents) family quickly believed she had died, and her mother said in an interview that they accepted not getting her body back, and that they felt they did not need it to grieve because it was not really her.
I also think LE ask parents not to physically look themselves (Keith bennett's family ask people not to make searches themselves too)
As for other parents, I do not think any two families react in the same way, it is such a personal thing. I think some families convince themselves there loved one is still alive, whereas other belive they have died. I know katrice Lee Major's family believe she is still alive, whereas Suzy Lamplugh (who was in her twenties though, but a child is still a child to the parents) family quickly believed she had died, and her mother said in an interview that they accepted not getting her body back, and that they felt they did not need it to grieve because it was not really her.
I also think LE ask parents not to physically look themselves (Keith bennett's family ask people not to make searches themselves too)