Euthanasia is a complex issue, it is killing a human life, helping a suffering patient die with dignity, and on both sides the fate of a loved one.
People who are against euthanasia would say it is wrong for someone to kill another human. They are against in because it would lead to involuntary killing.
People who are pro euthanasia would say it would not lead to involuntary killing. They believe that by making a patient suffer is wrong and they should not have to live with that ongoing loss of dignity.
In both cases, there is a life dangling with a significant amount of pain. Loved ones are in the toughest position. Do they prolong their life or ease the pain by death?