Kufr or not

As salam aleykoum, I watched a YouTube video where two man where helping people in the street and I think there are not muslims. One of them said “whe are looking for hassanat, we can called the video : the path to Paradise” or something like that. And then they laugh. But he was kind of making fun of the word hassanat when he said that and using Islamic terms or arabs words by non muslim usually make people laugh. So I didn’t laugh but maybe I smiled hearing that, and then I feel remorseful because maybe it is kufr ? Please can you answer me ? BarakallAllah oufik