BIANCA Jagger accompanied an eight-year-old Bosnian boy to a New Hampshire summer camp, where he will recuperate from heart surgery. Mohamud Ribic stayed close to Jagger when he arrived at the Interlocken International Summer Camp in Windsor. Her intervention brought his evacuation in May from the besieged town of Tuzla. Ribic was dying of congenital heart failure before surgeons in New York patched a hole in his heart. He stayed afterward with Jagger, ex-wife of Rolling Stone Mick Jagger.