A 55-year-old man allegedly killed his alcoholic son when the family was celebrating his granddaughter’s birthday in Pune district’s Pimpri-Chinchwad on Tuesday. Balu Baban Borkar, a labourer, allegedly killed Sameer with an axe when the latter came home in a drunken state. “Balu was…disappointed with his son’s bad habits and fed up of spoiling [the]…birthday celebrations,” a police official said.