Both Hadidi and Mohammad Abu Hattab, his brother-in-law and host, were away from Hattab's home when it collapsed. The Abu Hattabs' five-month-old baby also survived.
A spokesman for Gaza's Islamist rulers, Hamas, declared the deadly air strike "a war crime in its own right." The overall death toll in Gaza since Monday now stands at 139, 39 of them children. Around 950 people have been wounded.
On Monday, Hamas fired rockets towards Jerusalem in response to a bloody Israeli police action at the flashpoint Al-Aqsa mosque compound in annexed east Jerusalem, prompting Israel to begin air strikes.
More than 2,300 rockets have been fired at Israel since then, killing nine people, including a child and a soldier. More than 560 people have been wounded.