The parents deserve all the respect in the world for the hard work they do.
Few people choose to become drug addicts or to overdose.
It is well known that drugs like heroin, cocaine and tobacco are very addictive and dangerous, but to punish or ignore those who slip into addiction and tragedy would be like refusing to help accident victims on the grounds that they also knew the dangers or caused suffering to others. Society must wake up to the fact that we are all in this world together, like it or not, and start showing more compassion for those in need for whatever reason. Then maybe we can start to repair some of those tragic lives.