Strange. However, there is Amtrak from NYC's Penn Station to Baltimore. Son will have to take a taxi from JFK to Penn Station (34th Street & 7th Avenue) and find the Amtrak terminal and get himself a train ticket to Baltimore. Silly question, but if he is flying from London, why doesn't he fly to Washington DC instead? That would save him a WORLD of inconvenience.
Your son scheduled part of a trip without the other part?