when you shoot a dear and it still breath... do you watch it die helpless or you do what's necessary? what would a lion do?
Eat him maybe?

There is many ways a person which can use to end his life including suicide, euthanasia... The only difference is that you get killed by someone else in euthanasia.
Never will support or encourage someone to end his life instead I will refer him to a psychiatric to treat him (talking about the OP case).
If he has an end stage cancer, painkillers even knowing that they aren't helping a lot, can reduce his pain.
For dementia & schizophrenia they need someone who help them. (not to get ride of them, this only will make the retirement assurance happy).
Finally, should we end a life of a young girl because she suffers during her periods? Someone who has a chronic headaches? ... Next years i think we will hear about theses cases!
Next thing would be we hear about relatives deciding to kill their grandma because she got dementia and can't decide that anymore.

Well, that would be eutanasia really. Reminds me on hitler on his "ending unworthy lives".
getting a bit slippery slope there, but regardless, i think that a topic as controversial as euthanasia will come to be more or less accepted in the future, as with many controversial things. take drugs for example, we're sitting here having discussions on having drugs be legalized, wouldnt surprise me if euthanasia were to become accepted in the next few decades (likely on the basis of free will to do what one wishes with their life).
I don't think so. Legalization of drugs only gets discussed seriously because marijuana has certain positive effects on health and probably less negative effects than alcohol. I think the harder drugs are not really discussed by normal people in the majority.
Next thing is the religious people that see it as a sin to commit suicide. They are influential and that can have a big impact too.
but its not just marijuana, take portugal for instance, when they decriminalized
all drugs 14 years ago:
https://www.thefix.com/content/decrim-nation-portugal-ten-years-later"Time: Judging by every metric, drug decriminalization in Portugal has been a resounding success. It has enabled the Portuguese government to manage and control the drug problem far better than virtually every other Western country.""
decriminalizing in the US as portugal has done would solve many problems, including the ongoing problem of overcrowding in prisons. but we all know prisons make way too much money for that to be brought up politics anyways.
another article:
http://content.time.com/time/health/article/0,8599,1893946,00.htmlas for the religion issue, the current generation is currently seen as the least religious generation in a long time, and i expect the trend to continue over the next few decades, as the next generation's children will likely lack a religious influence in their lives with the current, non-religious generation as their parents. as the trend continues, we can logically expect the influence of religion to dwindle in the future society.
http://newscenter.sdsu.edu/sdsu_newscenter/news_story.aspx?sid=75623You are right, hard drugs are discussed too. Though like you state, with the younger generation growing up, there is a problem with that getting to the edge of at least being possible to achieve. I mean many people will be convinced with marijuana but hard drugs are an argumentation that most not can follow.
Maybe it would need a small scale test to convince people. But even that sounds impossible at the moment.
And yes, it would be interesting to see the results.