Assisting a terminally ill patient end there misery with their permission, you should be able to be forgave. Honestly its kind of like if you don't they will just do it themselves and then they will just suffer slowly. A doctor pretty much has to do what a patient asks. So therefore they have no control over what happens in order to do his or her job. Its just like being on life support and then after so long they have to be taking off of it and that's basically like committing suicide to someone else.