Question Ladies 21 Year old and a 48 year old.

So my friend is 21 and she will be 22 in some weeks. I knew her in high we are close. So she meet this man and he is 48!! her and the man just started talking but she said they click and there conversation is great. She likes him and there just friends right now. But she says you never know what can happen. I don't know what to say to her really cause I'm like why? But then again he makes her happy. What do you guys think about this and what do you guys think I should say? Thank you all!