I think we have to look at Benson and Randy as mirrors of one another to understand them. What we see of Randy mirrors Benson.
Randys mother is overbearing? Bensons is mentally absent and bed bound.
Randy got recognised by the adult from their traumatic memory? Benson did not.
Randy got closure? Benson did not.
If the start of the movie is about what trauma did to Randy, the end is what trauma made Benson.
Bensons story about wanting to be a giraffe as a child is showing how much he wanted to disassociate from his trauma. He wanted to be a animal when he grew up. He was being traumatised by a grown man at school then coming home with the desire the play pretend in his head about his future. He wanted to disconnect.
Whereas Randy wanted to embrace what he did even if it guided him into complete passiveness. He let it consume him.
Benson disassociated from what happened to him so much that in the end when it comes time to tell Randy what happened to him, to tell the audience, he can’t accept it then either enough to say.
So he tells the giraffe story instead.
