There’s no need for something that complex.
Someone with access to a chess engine watches the game and inputs the moves into the engine as they’re played. If there’s a critical move (only 1 or very few of the options are winning/don’t throw the game) they send a simple signal to let him know. That can be enough to give you an advantage at that level. If you really want, you could send a number between 1 and 6 to represent which piece the engine prefers to move, but it’s likely not necessary.

That said, all the evidence he actually did anything like that is at best circumstantial (mostly statistical evidence supposedly showing how unlikely his performance was given his past performance and rating at the time, as well as known instances of past cheating by him - though the only confirmed ones were several years ago when he was still a kid and online rather than in person).

I read another article that said a lot of cheaters do consult software that will suggest good moves. I’m just wondering how you get a sex toy to transmit the data about all the pieces on the board and request it back. Is he squeezing a butt plug with his anus in Morse code with the positions of every piece? Is there a network attached device connected to pick up the signal and send a request to an API and return the Morse code to his butthole? If he can do all that, IMO that’s even more impressive than being an elite chess player