Advice Needed! Parents please comment on what you think about this...

I have never been married and never had kids so, I know what it is to be a kid but not a parent. Today a friend of mine called me to pour his heart out a little bit. He is a former colleague and a very good friend. His 21 year old daughter has fallen for a guy who lives in another country. This guy is 30 years old and they met online. He came to Turkey and my friend took him and his daughter out for dinners and really got out of his way to get to know this person. My friend is a more traditional type but he certainly outdid himself by agreeing to this relationship. After all, times have changed and children are more independent. Besides his daughter is 21 and will be graduating College this year.

After flirting online and meeting each other both in Turkey an in Europe for a while, my friend's daughter found out that this young man was also involved with other young women (plural!). She found e-mails which were like photocopies of his messages to her down to the minute details such as naming future kids. What a jerk! So, her heart was broken badly and she sank into a big depression. My friend and his wife felt very helpless and they were very sorry for their daughter not knowing how to console her.

Some time has passed and the man contacted his daughter on Valentine's Day and apparently sweet talked her into getting back together. They met in Holland last week and when my friend found out about it, he ordered his daughter to come right back and felt compelled to deliver an ultimatum. He told her, if she goes to live with this guy despite his cheating on her, she might as well forget her family. He believes a cheater will always be a cheater and I tend to agree with him. I lived through a similar situation when I was 30 and got pretty hurt. I still feel very ashamed of my bad choice.

My friend went to see a shrink and took his daughter to her as well.

I did not know what to tell him. After all, people seem to learn only from their own mistakes and if passion takes over, logic flies out the window. May be he needs to let her make a big mistake and pick her up when she needs support but my friend cannot even consider this option. As I said before, he is a more traditional type.

So, parents out there, what do you think? What would you recommend my friend? I am not much of help in this department. All comments will be appreciated.