I know it's a puppet! I still cried. The Mum finding nits in Abby's hair wasn't a puppet (must post that on a nits thread - get a chimp, it will find them and eat them).
I thought it was the best episode of this season - that new doctor and the nurse from Third Rock have livened it up a bit.
On the 80 year old kids thing...and I haven't watched any of this series so may be out of line...does it not seem like a bit of a modern day freak show? Two weeks ago it was the 'mermaid' baby, last week was the desperately overweight man, this week the super-aged kids, next week the conjoined twins where one only has a head and no body. Maybe I'm misjudging and there is some 'worth' in the programme but from the tiny bits I've seem it looks like the modern day TV equivalent of the travelling freakshow. Hard to see how they can justify it.