How long would a 15 year old be in jail for ?

My boyfrend who is 15 assaulted a 11 year old because he called his "sister" a slut . (Theyre just close freinds) He broke the guys cheek bone nd fractured his nose . He has a court date on July 20th . A few days ago he stole some bicardi from a liquor store because hiis frend told him to . He got caught nd is now being charged in court for assault and theft . He has a good lawer but I want to know if he goes in an estimate of how long ? thxx it means alot . <3 xoxo