Breaking up is hard to do, I reckon.
Lots of reasons. First, he is graduate. She was still in HS. Was she breaking up cause she found someone else? Was she pregnant by him? Could she have been pregnant by someone else? And wanted an abortion, but he didn’t cause he didn’t believe someone else got her pregnant. Or she wanted the baby and he didn’t? Did she give him vd? Did she renege on a promise to marry?
Men can get crazy with rage, and also, like the opera song, “Donna es mobile”....plus they are both young and cannot reason very well. A shtf situation.