Karl Brandt the father of the nazi euthanasia program:
“Like many other German doctors of the period, Brandt came to believe that the health of society as a whole should take precedence over that of its individual members. Because society was viewed as an organism that had to be cured, its weakest, most invalid and incurable members were only parts that should be removed. Such hapless creatures should therefore be granted a “merciful death”.
https://en.wikipedia.org/wiki/Hadamar_Euthanasia_Centre
Have her tour the euthanasia center since she is in Germany. Have her explain why supports involuntary euthanasia. If she is in favor of denying life saving treatment due to age without the persons consent...that is what exactly she is wanting.
I will say there is a difference between denying someone treatment and letting them die on their own, and what they did at Hadamar, which was hastening their death by poisoning or gassing them.