OAP tried to disarm attacker.
Belfast Crown Court heard Maurice Harris and his son John, 50, were "jumped" after going out of their South Belfast home to investigate a car alarm.
Mrs Harris, 79, who arrived on the scene later, suffered a mild heart attack.
Her husband was left with a broken rib and lacerations to his hands, while his son John suffered a depressed skull fracture.
The court previously heard that brothers Gerard Donegan and Kevin Moyna, both from Ross Road, Belfast, allegedly attacked the Harris family.
Donegan, 23, and 20-year-old Moyna are also accused of attempting to murder Mr Harris' neighbour Maurice McCracken and attacking a third family in the early hours of March 9 last year.
Moyna's solicitor said Mr Harris "very bravely" managed to "seize the shaft" of the hammer during the attack. The trial continues.