I have mixed feelings on this one. First I agree that he NEVER should have gotten on the first flight to Europe once the doctors advised him against flying. I know he had this long planned wedding but so goes life. His wedding plans do not give him the right to endanger others.
Now that being said, after he was already in Europe and they tracked him down in Rome and told him they had identified exactly which strain of TB he had and told him not to return to the US and to notify Italian health authorities I would have probably done exactly the same thing and did whatever I had to do to get back to the US. As a US citizen on US soil he has rights under our constitution. As a US citizen on foreign soil with that type of medical condition he would have been completely at the will of the Italian government and medical personnel. And believe what you may about our government, I personally don't think our government would have done anything to try and help him or return him to the US.
Being trapped in a foreign country with no rights is not something I would wish on anyone.
I can understand that rationale, him being frightened and all. But it doesn't say anything about him evading being trapped in a foreign country and forced into a dark prison. I'm not sure what they would have done but he could have at least gone to a US embassy or consulate and proceeded from there. And what about wearing a mask? Just because he was afraid doesn't give him the right to possibly infect hundreds of people (in 4 countries) with a potentially lethal (and virtually lifelong) virus. Again, the whole kicker here is that the guy traveled to so many places (likely without a mask) AFTER he was aware of his illness. I mean, you couldn't ask for a better place to transmit TB than on an 10 hour intercontinental flight. Surely he knew this. I tell you what. If I were a passenger on one of those flights, especially on the last leg to canada, I'd be beyond upset.