No, it’s not hard to see someone elderly resembling someone young. It’s done all the time in this series.
It’s hard to see a tall beanstalk of a man supposedly looking like a short stocky man. Bone frame doesn’t change. You can shrink and inch of two, as you age, not a foot!
These writers/creators do not normally miss something like this. Important key to detail is what they do. This young Henry towers over everyone! So, only other conclusion is what RumplesGirl suggested. It’s a parallel of how one man can be beaten down in size.
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Keeper of Pandora's Box & The Yellow Brick Road.