No it isn't, they use it all the time - "wenn, was, wo" all read as "v". The "double u" sound is the thing that trips them up - it's common in slavic languages, not so much in germanic ones. For slavic the polish ł or russian "lambda" symbol sound like the "w" in wet. Could also be the accent, but I would wager it was more wires being crossed and saying "wet", instead of a problem with pronounciation
That's true, but I come across a lot of German speakers and I can attest that they seem to find it difficult when speaking English. Or they mix it up a lot anyway. I do it myself fairly often in Dutch with V and F.
Yeah, could also be that, but OP said "told us". Which means they used "w". Unless the sister made a mistake too. But then again, why would she say that in english. Vet in german is "Tierarzt" which isn't close to the english "veterinarian".
I'm just saying I've seen plenty germans text that misspelling. "are we going to the wet tomorrow?" would be a classic misspelling of a German writing English