Is "see off" still used. For example "I went to the airport to see him off"
I ask this because when I asked an American who is a colleague, he laughed and said I have not heard this word for years.
Did your colleague tell you what he would use?
Due to security you can't really see anyone off any more. You can drop them off at the airport and that's about it.
I don't think the words are dated at all. (And how rude of the person to laugh at you for your choice of words anyway!)
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.