boy still alive after being trapped under sand

An eleven year old boy buried alive for thirty minutes before being found.  The boys name is Nicolas Nelson, and he was digging a sand pit with his brother then suddenly the sand collapsed and he was under.  His 16 year old brother called the police in a frantic telling them to hurry.  The article went on to say, “Me and my brother were digging in a sandpit and it collapsed and my brother is stuck under there now,’ Kyle said to the dispatcher.  ‘I tried to get him out, but I couldn't dig fast enough.’  Kyle was soon aided by the brothers' mother, Aimee Nelson, and her boyfriend in feverishly trying to dig Nicholas out from beneath the sand.”  Going through this must have been hard.   The article said he sat under there and began to say goodbye to his family in his head.  It said, “Under the sand, Nicholas settled into a seated position and began "saying goodbye in his head," he recalled, to his family members above.   The 11-year-old was able to get a small air pocket around his mouth and it was those few inches of air, rescuers say, that kept Nicholas from suffocating.” 

I’m not one one hundred percent on this story because how can you stay under a sand pit for almost a half hour and not sufficate when it takes on average three minutes of holding your breathe to die.  This story is a little confusing in some parts because one: how did the sand not crush him, two: how was he in sitting position.  I don’t know this story just doesn’t add up in my opinion.