I feel that it's their business.
Just because someone is in the public, we don't need to know everything about them.
Let them have a personal life too.
If you want to permanently break off any form of friendship with the said relative, keep an annoying sense of guilt about whenever you see him or her, and act the as s to gain a bit of money then go for it
I say pass it on. No press is bad press. They depend on that kind of stuff to keep them buzz worthy. Just make sure its not something that only you would know, that is how they find out it is you!