My question involves criminal law for the state of: Massachusetts

My 17 y/o son was attacked by a 18y/o when he tried to step in a break up a fight in which the 18y/o then turned on him punching him in the face several times and the proceeds to kick him in the head while he was on the ground. I did file charges and the officer said it will be charged as an assult and battery and shod foot and the attacker will receive a summons..my ? Is what should I expect next and what can I do to make sure he is prosecuted..thank you