You really don't understand, do you?

Yes, citizens of the EU can get health care in other EU states. This tells you nothing about the treatments that are available in the different states.

Almost every treatment available in the US is also available in western European countries. Where this is not the case, the treatment concerned is usually one for a very rare condition. This is simply a function of the size of the population in the US, which is so much greater than in any individual EU state. The condition will, therefore, be seen more often.

There is no standardization of treatments available in different countries across the EU.