There are some harsh comments on here. I dont think it has been mentioned about Mark's fiancees mother taking him in after her death. I admire this lady. She cannot have blamed him for her death, or introducing her to drugs or she would not have been trying to look after him.
I think it is unfair to say that he should have been taken forcefully for help. Perhaps only a professional would have judged his emotional state as dangerous. How do you recognise someones passage through grief has moved from that to being totally overwhelmed? If it is easy to see and help then many suicides would be stopped.
I am not a fan of the police, who I know to be very heavy handed, and lacking in common sense, in some situations. But you cannot expect any sudden death in those circumstances (hers) to go uninvestigated. I am sure the guilt he felt would not have been made worse by anyone else.
I expect both of these people expected to live happy and successful lives. That they didn't due to drugs is a tragedy and another warning that it is not possible to enter the world of drug taking and naively promise yourself you will be very careful to keep control and be safe..
The fact that they were not known, or barely known, to most people, and were drug users, does not make their demise any less sad.