They didnt Even explaining to Him properly why he just wamted to go and live Nice place for his retirement so we realised it's not just money it's status and connection but Also got be something else ... becouse those who are not legit ones can Even Open bank accounts and living nice there but why they refused honest person got me thinking it's not Even about money just something else what play here importance
When people are refused residency, immigration officials will tell the person the reason for the denial. Even if they refuse to give him the details, he has the right the request information about the grounds for this denial. I don't think money is the only criterion for granting residency in a foreign land, other issues such as criminal records, health status and even your country of origin are also considered. With the increase in criminal activities such as mass killings, attacks on schools and other security challenges, most European countries have become stringent in issuing residency.
But if you are legitimately in the country and you have the right to have a bank account, you could report to your country's embassy or seek the services of a financial expert or legal practitioner.
I would have loved if OP had shared more information like the country of origin of his cousin and his country of residence, that should have given us more insight into why he was denied entry into Monaco, and refused account opening. Except it's an issue of corrupt officials in the immigration that wants to be bribed, then there must be perhaps something that he didn't tell you, because I don't see any reason why a person will meet immigration requirements and still be denied.
Immigration can have a good reason to deny an immigrant entry into their state or country, it could be because of criminal record, health or relationship with migrant country. Financial status can be one of the requirements for entry, but I believe that if an applicant doesn't meet the other requirements, then he might be denied entry.