Is it permissible to take from the money of a father who deals with a Riba-based bank, and is it obligatory to investigate the source of a shop owner's money when buying from him?

It is not permissible to take or spend from the father's money if its sole source is usurious transactions, except in a case of extreme necessity and the absence of another permissible source. If his money is mixed with both lawful and unlawful earnings, then benefiting from it is a matter of scholarly disagreement. There is no obligation to ask the shop owner about the source of his earnings, as the Prophet, peace and blessings be upon him, and the righteous predecessors dealt with Jews and polytheists without questioning.