Tom Parsons is a foil for Winston Smith. Tom has a family; Winston does not. Tom is a working-class automaton; Winston is not. Tom swallows his Victory Gin and the Party propaganda without question; Winston does not. Tom is grateful he is turned in to the Thought Police by his own children; Winston is not. Or so we think...
Parsons is introduced in Book 1, chapter 2 thusly:
Parsons was Winston's fellow employee at the Ministry of Truth. He was a fattish but active man of paralyzing stupidity, a mass of imbecile enthusiasms—one of those completely unquestioning, devoted drudges on whom, more even than on the thought police, the stability of the Party depended.
Enotes has this analysis of Parsons:
Eventually, his daughter turns him in for Thought crime because he says “Down with the Party” in his sleep. He tells Winston he is grateful he was turned in before his terrible thoughts became conscious.
Winston does not want to become Parsons. That's why he keeps a journal. That's why he visits the antique shop. That's why he dreams of Julia and O'Brien and the meeting in the place where there is no darkness.
But, inevitably, Winston ends up just like Parsons. So says eNotes:
[Winston] has a strange respect for his torturer, O’Brien, and seems to enjoy their battle of intellect, ideas, and wills. Indeed, he has been thinking about and fascinated by O’Brien for years, even dreaming about him. In a way, he seems happy to be confronting him at last.
Both men are addicted to pain in the end, happy to be tortured. Torture is easier than freedom; it quiets the brain, at least. So, what happens to Parsons foreshadows what happens to Winston.
I think Winston knew the Parson's a long time from before, they were his neighbours, he helped a lot the parson's woman, when she had 'an amateur repair job' for him to do, Tom also was one of the Ministry of Truth-workers where Winston also worked, however Tom worked there as a laborer and Smith had an administration function, Smith was more intelligent than Tom and his children Parson's, and saw the Party as where it stood for, and as Smith knew that wasn't any good, Tom and probably his children thought of themeselves as very much 'in line' with the Party, and so they must of themselves have thinking that nothing bad from the Party could have overcome them, because they were so 'in line' with the Party, however one day Tom's daughter denounced her father to the police, and so he also came in the Ministry of Love where he at least should experience a little bit of torturing, I'm not speaking of Tom's wife probably she was more intelligent than her husband and children, and that was the reason she was depressed, she might also from before have visions of herself, her husband or someone else whom she cared for to become in the hands of Ministry of Love-workers, I also think of their children that for the time (certainly as long as they remained children) they should not have to have become afraid of what might be happening to them from the Party, but maybe as they should have become older they might also easily be overhanded to the Party for a little bit of torturing, nobody was save, remember!