Was he ever that happy in the movie? 
The "smiling with closed eyes" reminds me of anime, but since he's an old man it sort of makes sense.
why yes he was
What is odd about it is that he is saying a greeting with his eyes closed.
In the reference he looks like he's sitting down and really relaxing by himself without anyone around.
It would make more sense if either the "yo" was gone or his eyes were open wide.
In your reference, the chin really sticks out with a highlight near the top.
Your bottom jaw is similar but I feel the dark line for the mouth detracts from the shape of the chin and flattens it.
With some pretty simple rendering steps including nose shadow on the upper lip, you won't need such a dark line.
As mentioned, you should make better use of the light and shadow in the reference to help bring out the forms.
You've also squared off his belt instead of letting it curve over his belly which again, flattens the forms.
