It's hard to know really. Red Bull themselves said before the COTA weekend that that track ought to suit them more than some others.
We'll see. I think Mercedes still have the fastest car at most tracks (as they have since Silverstone), but Verstappen just needs to win 2 races after which he can almost certainly settle for second place if needed.
Several scenarios are possible where they could be tied on points. The most likely one would be Verstappen winning 2 races and Hamilton winning 3 (including 28 points at the Interlagos sprint weekend) plus 4 fastest laps, with the 5th fastest lap going to another driver. Other scenarios are perfectly possible too of course. Such a tie would almost certainly favour Verstappen as he 2 more wins than Hamilton currently.
If Hamilton wins 4 races he's almost certainly the champion, even if Verstappen gets fastest lap in all and 28 points at Interlagos. If Verstappen wins 2 races he is likely the champion.
The big unknowns are if Hamilton needs a new engine and whether Bottas and Perez can step up and affect the other team - a single race with eg both Mercedes ahead of Verstappen would likely sway it in their favour. Or if we get a wet weekend, which is only likely at Interlagos (Mexico City gets barely any rain in November and nor does the Middle East).
There's still a long way to go though. A lot depends on whether Hamilton needs a new engine. If he does, Verstappen is likely to win and would then just need 1 more win with the rest second places (assuming Hamilton doesn't get fastest lap in every race). If either driver suffers any unreliability or crash damage they are almost certain to lose the title. Thankfully I think Perez isn't that type of driver (anymore) and Bottas is unlikely to try any funny games since he's out of Mercedes anyway.
