sergers parent
i think she was "working" but potentially unpaid/compensated in lodging staying a t https://www.workaway.info/ (which was reported by the BBC where she was staying)
This site now has a popup for the US
> Important information about visiting: United States > If you are NOT a US CITIZEN and are planning to visit to work, volunteer or study, YOU WILL NEED THE CORRECT VISA. To find out more information you need to contact the embassy in your home country BEFORE traveling.
But a quick look around near me looks like work for immigration purposes, so someone on a tourist visa to the US should not be participating.