dustbank is correct in his opinion. only option is to send bill to first magazine and demand the claim. or send a legal notice for your right.
This is one of the reason why I am a member of a Photography association. They help with these kinds of cases.
I would first contact the magazine that has used the material without approval. They are the ones that are wrong and should have known this. It might very well be that there was an unexperienced editor that did not have a clue. So keep it friendly at first, your friend might end up with an extra client in the future. If this can be achieved it is the most desired situation.
If they refuse to pay for the usage your friend can always go for the hassle of legal action. I am glad I never had to revert to that. I have had about a dozen court cases over the last ten years (over various other matters). No matter I lost or won it always costed me money. My ego is small enough by now to walk away if I smell something will cost me more than I gain.
That is my personal opinion. I know there are people that want to take these types to court no matter what as a matter of principle. Fine, they have a point but I have had my share of court cases. For me the court is like a gambling machine, sometimes you win sometimes you loose but the house always wins. It will always cost you money.
Legal cases can cost significantly. Depending on the type of case and the party you are up against. If you are fighting a large corporation that has almost unlimited funds, their own legal department and their own dedicated law firm you are better of trying to negotiate your way out of it. It has cost me almost everything I once owned and about 10 years of my life.
Again this is all just my opinion and part of my own experience.