Attempted Burglary, and Tresping Help.?

My brother was recently indited on some bullshit to say charges. Attempted burglary, and Tresping. He, and 3 other people went to this guys house, because he had stolen someones weed. 2 went in, and beat up the kid, while 2 stayed outside on the street one which have been my brother. He never entered the premises, or attempted to hurt anybody. He wasn't a accomplice, because he never went in the house, and the Dad of the kid refused to press charges, but the Police Office sayed it was there choice. He could face major penalty for not doing anything. Could there be a legit argument of him doing nothing, or can they just charge him on nothing. Detail please.