OK, I understand your question now.
First, "retargeting" is not about to made illegal. What your friend is probably thinking of is the EU "cookie law". This says that, if a website uses certain types of cookies, it must notify the visitor of the fact and get their approval. If the visitor declines to give approval, the site is not allowed to place the cookie.
The "certain types" of cookies include those used by ad networks to track visitors so that they can better target their ads. This is no doubt what your friend had in mind.
Exactly how the new law will be implemented is completely uncertain at present. It's due to come into force in a few weeks time, and it's up to individual states to issue guidance about how it will be enforced. There's been a lot of discussion on the subject, so I won't repeat the arguments for or against, but if your friend has a website that contains the type of ads I am talking about, they will need definitely need to look into it.