During the course of my work I have seen doctors make some of the most dumb ass decisions concerning pain control possible. Things are getting a little better but not by much. When you have a patient who is totally eaten up by cancer and the doctor will not give morphine for fear the person will get addicted it is a decision that boggles the mind. My God, this person going to die! Who cares if they get addicted?That is the least of their problems. You bring up the comparison of those who have survived concentration camp. There is a major difference there. No matter how awful the situation they had one thing that could pull them through and that is hope. For a person in the end stages of a terminal illness there is no hope. When you are in constant horrible pain with no hope believe me suicide looks good. If the pain factor is addressed properly people can often find the strength to see it through to the end naturally.
Another factor besides physical pain that often makes people consider suicide is watching the suffering of their family members. Everyone is trapped in a situation that only death will free them from. I have seen wives and children have total nervous breakdowns trying to cope with the pending loss of a loved one and are just unable to come to terms with it. For the dieing person they too must carry the pain that their family and friends is experiencing. Nine times out of ten families are profoundly effected by the process. It does not make for the happy little Walton's moments where everyone makes their peace and all is forgiven and understood. It is much more complex than that. Everyone's got their stuff, everyone is suffering and the terminally ill person knows this and can change nothing. The movie and books like Tuesdays with Morrie is not the way it usually happens. Sometimes it does and it is wonderful to watch but for many it is long drawn out stupid suffering.
I have had many discussions with terminally ill people on this topic. What I always advise them is to to make suicide their lost possible option not their first. I tell them to have people outside the family tend to their physical care as much as possible so that wives and children are given a chance to come to terms with the situation. All hospice organizations offer help for the family and they should be encourage to take it. I also tell them to speak to their loved ones from the heart, to apologize for past mistakes and set things right to the best of their ability. If their doctor is not addressing their pain then find one who will. Often when all these steps are taken suicide no longer seems the only way to cope.