Do you think they made it? If they did would they be prosecuted if they were arrested today? Should he receive medical treatment?
If it was for real I would contract a major newspaper not a police station. Second if he been floating around for sixty years or so free he would likely have a false ID that would likely give him SS medical coverage. The whole thing does not sound likely.
Obviously this no longer matters if he had cancer without treatment in 2013. Only the governor of the state of conviction or the president could have made the deal. It would have been a deal to make because of all the info that could have been learned about how all 3 stayed off the radar for 6 decades. However, the reason not to do so is to not reward a prankster, if that is what it is. Maybe it is an author hoping for PR to sell his book by raising interest in the escape. That the FBI said fingerprints and dna were "inconclusive" lends credibility to the letter, as opposed to coming up with positive negatives by both accounts.