Stable angina at rest?

My 88 year old grandfather gets angina symptoms, a painful tightening of the chest that can extend through his whole body. They occur when he is in bed, late at night or early in the mornings. The doctor says he believes the angina is of the stable variety because it has been ongoing for a while (a few months) and it has been in a pattern (either night/morning but not other times of the day). If the pattern or intensity were to change, he says, it would be called unstable.

However, the Internet sources I've read all say that angina at REST is the DEFINITION of unstable angina. That means there is no physical activity he can avoid, it can happen anytime. That would put him at risk of a heart attack and he would need to be monitored and stabilized in a hospital until tests and possible angioplasty can be performed - and drugs like heparin and glycoprotien IIB/IIIA inhibitors can be given.

Doctor says he is not in a rush to do catheterization - he wants to see if my grandfather will respond to medication (metropolol 25mg, aspirin 81mg, isosorbide 30mg daily) that he started a few days ago. He hasn't had any testing on his heart.

Has anyone heard of a stable angina at rest?