How many years in jail for blackmail?

My little sister sent some pictures to her boyfriend when she was 15 or 14 she is now 16 her was 18 when they started going out and he is now 19, he would control her in every way and force her to do things she didn't want to do, like sending him nude pictures. Last week he posted those pictures on facebook, I wanna know how many years in jail he could get or any other charges??