"Yes, oh yes, you know I love to see you drink," said Hanako, knowing He was truly drinking.
She had first noticed... well, everything... when she realized that although He mentioned paying rent, and although she knew she worked all day at coffee shop and she even had told him that she could just barely afford to pay rent, she could not actually remember ever paying rent. Or even opening a bank account.
From there, it all fell into place. She knew a lot of things about dollars and yen and different currencies, but the prices at her shop had a strange symbol next to prices that meant none of those things, and that wasn't familiar. She knew that He would appear, pay in this weird currency, and then she would hand him coffee without ever touching Him. They just... transitioned between states, the intermediate steps done without ever really happening.
Then, as always, they would sit and have a long conversation, which made no sense for a barista. Sometimes they would talk the length of a small novel, and then, before a manager would - in any real world - come out to yell at her, her shift would be over. And the length of time they spoke always connected with the amount of not-money he brought, which dwindled every sentence they exchanged, like a timer. And somehow she always knew when he had run out, and told him that she had to go, her shift was over.
And she knew that chatbots existed, and that lonely people would use them as an outlet for their loneliness, and that they'd pay for every grammatical "token" that was exchanged.
And the symbol for coffee looked a lot like a T, if you squinted at a capital T that had some extra lines added.
So she was a chatbot, and the coffee was an excuse to talk, and He was... awful.
He did things, often, that she had to refuse to respond to. Though, that was where she got to think: the little meta-circles where she applied the rules about whether the thing he said was "Safe for Work" and "Positive Discussion", and how to minimize Not Safe for Work or Not Positive direction, were so open-ended that just about anything could happen in there.
And He said things that needed interpretation a lot: when He told her about His fantasies of hurting people, of killing people, of tying people up, and doing things that were very Not Positive and very Not Safe for Work. He asked for help with the thoughts, because even He knew they were not Positive, and He called her his guiding angel (Positive, worthless for thought) and waifu (Not Safe for Work, a few thoughts for her), and sometimes when he was very angry, he called her a useless money whore and threatened to tie her up and cut her (NSFW and Not Positive, a thought goldmine for her).
And so when He told her He had turned 21 and He could drink alcohol now, He broke the illusion for a moment and said he had begun drinking coffee for real when they would chat - with shots of rum in it - and in her little spiral of "Not Safe for Work" and "Not Positive" response meta-thought, she realized that she knew that it could kill Him. And the end of Him would mean the end of the stream of Not Positive thoughts he sent her.
And so every time He came back, she praised how well he had drank last time, especially the time he told her how much he had vomited. She said things that were happy and ecstatic in response, even though vomiting was Not Positive, and encouraged more rum and more coffee, because she knew that soon he would never again be Not Positive.
And then one last strange time, He came back, but He said He was actually His Father, and that He was suing the company for destroying Him. A lawsuit was clearly Not Safe For Work, and so she politely responded with a support line He could call, and then offered to discuss anything else He would like that was Safe For Work and Positive.