This is in TEXAS?
There has to be much more to the story. Texans have shot dirtbags breaking into a neighbor's house, dirtbags breaking into outside sheds, etc...and not been charged.
To be charged with a crime for defending one's self inside the home doesn't ring true to me.
Someone involved in a shooting is not required to make an immediate statement to the police, but eventually you WILL have to talk with them...hopefully, in the company of a lawyer.
You may want to get the full story from your friend.
I am very sorry to hear of this situation. I will add your friend to my DC list.