She doesn't have any boys, only two girls: Alma Jr. and Jenny…and they have the type of relationship with their father that suggests they won't want to be anything like him.
We barely see baby Jenny, but Alma Jr., the older daughter, is desperate to have a relationship with her distant dad. She even asks Ennis if she can live with him, but he turns her down, because he wants to have the flexibility to see Jack whenever he wants.
After Jack dies, Ennis makes amends with Alma Jr. She's the one link he has to his family, because he's ruined his relationship with his ex-wife. It's difficult to tell if Ennis would try to rebuild his relationship with Alma Jr. if Jack had remained alive, but once he's gone, Ennis' priorities shift away from his dead lover and towards his living daughters.