About voluntary active euthanasia

We might oppose voluntary active euthanasia even while we support the permissibility of physician assisted suicide because there appears to be a causal distinction between the actions. Carefully describe Brock’s two responses to this view.
One might think that the importance of autonomy as a reason for voluntary active euthanasia diminishes in certain circumstances (like advanced age or terminal illness). Carefully explain both this view and Brock’s response.
A standard view is that the permissibility of voluntary active euthanasia is grounded in two medical values, autonomy (or self-determination) and individual well-being. But we might worry that there is a conflict in relying upon both of these principles to reach that conclusion. Explain this potential conflict. How does Brock resolve the worry?
How does Brock respond to the objection that even if individual cases of voluntary active euthanasia could be justified, a broad policy would be a bad idea?