Hi Zen,

If it were me, I would end the friendship with this person and find some other people to hang out with. And I wouldn't tell this person the friendship is over... I would just stop returning their phone calls, emails, etc. Sooner or later, they will get the hint.

Anyway... You say you conduct business with the parents of this friend.

What sort of business? Are the parents your employer, boss, clients or what?

You also mentioned that the parents have said that they don't get involved in their children's arguments. If that is the case, then the termination of the friendship probably wouldn't affect your relationship with them.

And IF they were to ask you about why you no longer hang out with their daughter... all you need to say is that "We just don't have much in common anymore."

That's all the explanation that is necessary. There's no need to get into anymore details than that.

Anywho... good luck to you.