They laughed. Apparently picking up Spanish from your Spaniard friend has some downsides.
As in South American backpackers find it funny/amusing this drunk Chinese guy in an Australian pub used the Castellano equivalent of "y'all" in a sentence.
They were ultimately nice about it, much better than the time my (English speaking) Canadian coworker tried to speak to some Parisians in school level Québécois and they scoffed and continued in English.
While English became the lingua franca (and I fully get the irony of using the term "lingua franca", lit. Language of the Franks, to describe English as opposed to French), the quirks of being separated by the ocean(s) is fairly minor like, the f slur referring to a cigarette in the UK vs being a... slur in the US, or trousers vs pants.
For some reason, Québécois has stayed way more isolated and thus archaic sounding compared to Metropolitan French. Not just in phrasing (Québécois has a lot of terminology that relates to the church), but also pronunciation. E.g., the the way "r" sounds are made in Québécois is actually closer to what Parisians a couple hundred years would have sounded like, instead of the "w" ish sound Parisians say now.
Imagine if North America spoke mostly French, instead of English...