Consider the Ramada at Kennedy Airport - its an acceptable hotel with parking. Will set you back about $165 + tax - perhaps better through some of the internet discount sites. You will be 5 minutes from the terminal - and as your parents will have been travelling for 20hrs - you could take them back to the hotel, they could have a nice shower and refresh themselves - perhaps even a nice breakfast - before setting off on a 4hr drive.

As I too have elderly parents and am very concerned on how they travel (and when they come to visit us in Europe its comparatively short at 8hrs)
I would personally stay near the airport and provide them with the facility to shower and rest a bit before setting off for 4hrs

Trusting your parents have a comfortable and safe trip