Of all the times I've heard people try to shift blame, this is the only one where I can partially agree:
He is a 15 year old ADULT. He is capable of reproducing. He is aware of what life and death is. He made a choice.
Adults his age in the not too distant past were commanders of legions of other (12+ year old) adults.
The only blame on the parents is: Parental awareness.
How could anyone simply ignore their child for 4 days? That isn't a parent.. That's more like a provider. The government.
It makes you wonder if his parents left him alone like this as an infant as well.