No one saw something strange in a 27 year old “man" dating a 16 year old girl?

I remember I had a friend that have a sister that stated to date at 15 with a 25 year old “man", when she told me I saw something strange, but she laughed and sai it was fine.

I can’t say what is happening right now with this friend, we walk different paths, but it isn’t normal this behaviour. Of course for a teenager girl sounds cool date a “man" in his 20s, but what is the price?