How could I contact my deseased son?

My son ped away in April 2008, I miss him dearly and it was a complete shock... His name is Nathan and he was born with CP but he had a more severe type called athetoid dystonic spastic cp it effected all of his muscle movements and he could not walk,talk,eat or even sit up by himself he ped at the young age of 4 yrs old, he aspirated on his gastric content secondary to his disabilty.. I still have alot of unanswered questioned and I know that it has been over 2 yrs but there s no other pain worse then losing ur child please help!!!