I was trying to make evident by way of requesting the definition that suicide can certainly be seen as selfish, in some cases. It certainly is a decision one often takes as a result of overriding the will of close ones, which want or need you to stay alive.
But what is "selfish"? Putting your own needs first, which we do all our lives? Are the close ones the selfish ones for blocking your wish? When is putting your will first reprehensible, and when is it not? It seems like a blurry field, that each camp can bend as it suits them.
I don't think that it is necessarily selfish for someone to do what is best for themselves. People do what is best for themselves in a given situation all the time, and outside of suicide, no one questions it. As far as suicide being selfish, I think that it depends on the reason they are coinsidering suicide. How bad is their situation? Realistically, what are the chances that given time that their situation will get better? If there is very little chance that their situation will improve, can they learn to live with it? In the end, the decision is theirs to make, because it is their life, and they are the ones that have to live it in the current state. Someone else who has never been in their situation and has no idea what it is like to walk in their shoes everyday has no say in what they should do.
As for the suicidal persons family and friends, I would ask them what they are doing to help them. Do they call them to see how they are doing? Do they visit them often? Do they do anything to help them in their situation, if it is possible? If they don't do anything practical to help them when they could, and at minimum don't even offer emotional support, they don't really care about them and are the ones who are being selfish. To expect someone to continue to suffer unbearable pain for years and not do anything to help them is cruel and selfish. If the suicidal person's relatives/ friends don't want them to commit suicide, they should spend some time with them and try to help them, or if they can't help them, try to find someone who can help them. They shouldn't refuse to help them, and then complain that the suicidal person is selfish after they kill themselves.