The end showed how old and neglected this dog became because he kept running away - when he died, he saw the professor coming for him, and all the stars being out in the evening. The professor’s widow recognized him. I suppose she felt bad because it was going to end this way and she wouldn’t have time to help him anymore. Akita dogs have a ten to twelve year lifespan, and they are very big dogs. They have a tendency to favor one person, although they are good with the other family members.
He literally wore himself down chasing after the person who gave him a home.
I think I recall the scene where the dog catcher was taking a small dog to out of the cage be put to sleep. He said they couldn’t take Hachi (that was the beginning of the story.) The shelter was overcrowded.