Are the children entitled to claim their father's inheritance that he bequeathed to their cousins?

You are not entitled to claim what your father gave to his nephews if he gave it to them while he was in full possession of his mental faculties, because a father has the right to dispose of his possessions. Scholars have stipulated the permissibility for a strong, earning individual to spend all his wealth, as Abu Bakr Al-Siddiq (may Allah be pleased with him) did when he brought all his wealth to the Prophet (peace be upon him).