I believe in circumstances where a terminally ill patient can speak with and talk to a doctor about the right to die and the doctor can concur that their prognosis will only get worse, then prescribing lethal drugs should be an option on the table. There is no need to have people suffer, just because others have a moral issue with their decision.
Although there are many medical advances being brought to light daily, one who is suffering for a disease that has been deemed terminally ill should be allowed the right to determine their own fate. If an ill individual decides that it is easier to take a lethal drug to inhibit a quicker death that there is no way that any other person could rightfully have a say in the matter. The question states whether its justifiable and well being told your disease is "terminal" and you cannot be helped isn't a very justifiable situation to live in. Every human has a right over their fate.