Odaat,
My dad was treated through the UPMC system in Pittsburgh nine years ago and it is one of the best in the country. I spent many hours in the cancer center information center/library there.
I would think their social workers would be versed in some of the insurance issues, or could refer you to someone who is. Also, a great resource could be the benefits administrator in the human resources department at your employer or at your son's former employer. They know all the COBRA rules (in case your son is still eligible for that) and they often are aware of alternative insurance resources for these kinds of circumstances. Good luck and let us know how things go.
Joyce (Pittsburgh native and Steeler fan)