A son has lost a court dispute with his sister over a Sydney home valued at about $7.5 million, after arguing that their mother had promised it to him for almost four decades. The ruling means his claimed entitlement was not upheld, underlining the difficulty of enforcing informal family assurances about future inheritances.

The case centred on a property in Coogee and a long-running alleged promise by the siblings’ mother. Despite the son’s account of the arrangement, the court found in favour of his sister in the bitter family inheritance battle.