You'll probably argue that my father means actually he wants to do a Powerpoint - which would mean that not only he would like to create a presentation, but also use the exact same software he's used to. Could be, but I don't think that's the case. Actually he seemed pretty open to use another software. He actually likes to use Chrome, which is not a browser he was used to. But he only knew of a presentation as a "Powerpoint".
Let's accept it, we all use, at least sometimes, "word" or "excel" as common nouns. That makes a whole difference for web search, for example. You're unlikely to find Open Office if you search for powerpoint.
The vocabulary in itself is locking people into one brand, without any file mechanism involved yet! The question then becomes - what is the alternative wording to Word, Excel and Powerpoint? Well there isn't really one. At least not one so succinct. "word processor"? Too long. "Open Office Writer"? How can you put that in a discussion: "Can you give me your writer about the economic crisis?". "Spreadsheet" is appropriate in English but it doesn't translate well in German or French for instance ("Tabellenkalkulationprogramm" anyone?). So we've got a problem here.
Someone will have to find new, better words for that. The more common the words, the most chance it fits to some more open document format - because that's what it's all about. Find standardized nouns for standardized formats. But enough of that topic. Maybe the best names are already used by Microsoft, and we'll have to move further to a new paradigm. Would it be better pushing people to just make "web pages", wherever local or not? Facebook is using "messages" and "updates", and is actually almost owning "friends". Words matter.