The doctor may have become sentient because something unforseen or unexplained happened to his program, but there's was no eureka moment where he declered "Yes! I am a real Doctor!"
If he became sentient, we don't know the point in the story where he transitioned from sentient to non sentient. It might have been a season 2 episode, or it might have been a season 5 episode.
No matter when he did become a person, the Doctor was treated like a floor model fresh out of the box the entire time, by a group of human beings (others) who loved him like their teddy bear, who is also not a person.
It wasn't his improved personhood which got him treated more like a person, it was their increased anthropomorphizing.
If he became sentient, we don't know the point in the story where he transitioned from sentient to non sentient. It might have been a season 2 episode, or it might have been a season 5 episode.
No matter when he did become a person, the Doctor was treated like a floor model fresh out of the box the entire time, by a group of human beings (others) who loved him like their teddy bear, who is also not a person.
It wasn't his improved personhood which got him treated more like a person, it was their increased anthropomorphizing.