You don't need to make the schizos believe false things when they do that on their own.
The person they kept claiming was Pippa that was dating a troon or whatever, I ended up looking into it when they first started going on about it and finding the person they think is Pippa was some chick who was working at a weed shop in 2022-2023 in Oregon, archived and took some screenshots, thought about posting it and then decided it was funnier to leave it alone.