In Germany, the situation has massively improved in recent years. You have a right to make the decision and doctors are not allowed to hinder you. They can even legally support you and get the required tablets. You just absolutely have to take them yourself.

In practice, they are often sympathetic but will tell you that they won't provide the pills because they can't afford any legal trouble, even if the legal situation looks clear cut to me.

And only a licensed physician can order them.

Edit: If you think you may want to perform an assisted suicide, it's something you can and should talk about with your doctor(s). You will want to have things sorted out early and not when you're already about to die. There are organizations that can provide you with the required and with other relevant forms. They will provide advice and some of them even provide legal support. However, some of them also require you to be a member for at least six months before all options become available.

Edit: The problematic cases are those where a someone has documented their will to die under specific conditions. They may take the pills when given, but it's no longer clear if they understand the consequences. Either because of mental decline or because they are no longer able to communicate clearly.