Weird Ending. Spolier
When I watched it, most of the time I couldn't look, I didn't think it would end like that. The more I thought about it, the more I realised it was silly. Afterall they had the wrong bloke, it wasn't their fault but when he was lying on the bed saying he didn't know their son's name but then he remembered it. Why did he not say I'm the wrong person and told them what he was in prison. Even just saying it would have put the seeds of doubt into their heads.
Another thing I don't get is why did he kill himself? Did he think he got tortured as a punishment? It seemed a bit excessive to me