What The $(%)# ....
Truth really is stranger than fiction.
A perfect storm of an exceptional liar, some incompetent officials and some fairly dumb people ('Spain is all the way across the country...') who might have had a secret of their own.
Obviously the thirteen year old boy was fairly troubled and there seem to be issues within the family, so who knows what really happened there. But to go to Spain to get a stranger to replace a child you might know was killed seems a bit far fetched.
Plus the imposter has a history of being a compulsive, unrepentant liar, so I can't say I really believe him.
This whole thing is really bizarre. Up to the fact that he is now free with a wife and three children of his own. Wow.