Friend’s Dad Asked Me Out

My (48f) friend is a bit younger than me and she (40f) invited me to her Dad’s beach holiday home after New Year with her family. Her Dad (65m) is a very in-shape, charming, intelligent and successful guy and we spend a lot of time discussing very interesting topics and generally just having a great relaxing time. He said he really likes me and he asked me out …I am quite taken aback by this. I didn’t mean to or think I lead him on. My friendship with my friend is very important to me.
I am finding myself thinking about it… I would appreciate a few views on this situation.