Havent seen the video yet but its a good question.
I’m not a pyschologist but anyone wishing suicide for him/herself is more coming from a sad and depressing scenario. So the key element would be to come out of depression or bring your loved ones out of that depressing modes where they really arent on their own. They just can do anything including suicide.
**One of the better ways would always be to motivate them, to make them count all the blessings whether physical or otherwise. And then all the good options they have got to make their lives better.
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Its one of the worst condition when one person goes so deep down in anxiety and depression that he/she starts getting suicidal thoughts.
And NO, just saying that suicide is haram, is definitely not enough. A person in worst state of depression needs far more than a religious fatwa. A very big effort of consolation and motivation is required which can actually be a real struggle.