TV is both a piece of furniture and a medium of entertainment. The article distinguishes which you mean.
You look at the TV as furniture, you look at TV as entertainment.
Your first example, to me then, is wrong. It suggests he was staring blandly at the box without paying any attention to whether it was even turned on. I don't think that was the intent of the writer, so I would leave out the "the" there.
Actually, I would change the whole clause to be more balanced, or poetic:
He smoked while he read, while he watched television, and while he drank coffee.
Did you see the boat race on (the) television? Oxford Advanced Learner's Dictionary of Current English, 1974
What's on (the) TV this evening? There's an interesting play on (the) television. A Comprehensive Grammar of the English Language, 1985
None of these examples require the "the" - in fact, its use is quite awkward.
Interestingly, however, the "What's on (the) TV this evening" - if you substitute a slang word for TV (Tube), you need the article. What's on the tube? But then, as you can see, the tube refers to the (ancient, former) technical aspect of the item, the cathode ray tube that was inside the box. That's why when we say "the" television, we tend to be thinking of the box, rather than the medium.
"Here, darling, go put this vase on the television."
"Turn off the TV and come to dinner."
"You spend too much time watching TV."