The victim should have the right to end his life, if he wants. But I think it would be a great mistake. However bad life may seem, there is always something you can do, and succeed at. While there's life, there is hope.
No matter what choice you make, it doesn't define you. Not forever. People can make bad choices and change their minds and hearts and do good things later; just as people can make good choices and then turn around and walk a bad path. No choice we make lasts our whole life. If there's ever a choice you've made that you no longer agree with, you can make another choice.