I think a lot is going to hinge on how the ‘6 months left to live’ thing is regulated/determined, who will make the call, who will the government force to be in the position of doing this?

That is very difficult to predict for individuals. We can say that "on average someone with this condition will live less than 6 months" or "I wouldn't be surprised if they die within 6 months". People vary. By the time we are certain it is less than 6 months it is usually final days/weeks.

The medical profession will revolt if there's not a conscientious objection clause...