Is it permissible to eat food and take money brought by the father, the source of which is doubtful, even though he claims it is permissible?

The default rule is that a Muslim's earnings are permissible unless proven otherwise. Therefore, it is permissible to eat food and benefit from wealth if the earner's acquisition was lawful. However, if there is a strong presumption of unlawfulness due to compelling evidence, then it is not permissible to eat or benefit from it except in cases of necessity. If lawful and unlawful wealth are mixed, then benefiting from it is considered reprehensible (makruh).