Wood shrapnel is horribly infectious, very easy for blood poisoning to set in.You can read about it in stories of men on tall ships who had to suffer it on their wooden ships during cannonades one hundred and fifty years ago.
Hope the dude is OK,and that they get it all out and cleaned up.
Green Bay Packers great Jerry Kramer almost died from wood splinters - http://books.google.com/books?id=SD3G3dyx2ZoC&pg=PA57&lpg=PA57&dq=jerry+kramer+wood+splinters&source=bl&ots=AmpnR4YcHi&sig=7CjYrgCKF1MJIknkugeO2nQD65A&hl=en&ei=9IaXTKieGISosQOynujACg&sa=X&oi=book_result&ct=result&resnum=2&ved=0CBYQ6AEwAQ#v=onepage&q&f=false