If Eames wanted to be sappy, which he isn't, thank you very much, he'd say that maybe the empty chair had been Arthur's all along.
This made me seriously go 'awwwww'.

I love the imagery you depicted. A glimpse of Eames' childhood. Something special and personal. And I love that he somehow subconsciously admits that despite Arthur's difference, he belongs in there. With Eames. Just. &hearts