I reckon the guy will die a few chapters before we reach the half-point of the last book. Just as the story will start picking the pace up, that is, and then our trio will have to deal with Tohnos unified more tightly than they ever were.
Because even with their "uh oh, we be evil" vibe, they aren't idiots, and to convince them to side with someone who has bigger plans, that person has to be charismatic, which Rowling's Tom was not. And there's also the fact that to even think of recruiting them, Tom would have to think about people as, you know, actual people (even if merely "people useful for my plans") instead of tools, like he did in Rowling's books.
But then again, the political situation is very different from the one in Rowling's books. It wouldn't be easy for him to engineer a take-over of the whole wizarding nation of Britain, not with Bones as the minister and with ICW monitoring the situation. And since the support for muggle-borns is greater than in the original books, too, in the eyes of someone like him a thorough cleanse of the country might appear to be the better option. Moreover, there is a group of people with connections and rather high potential for wizarding magic that is actively trying to oppose him (that group being the original trinity), and they were actively trying to screw him over for the last ("at least", from his perspective, that is) three years.