I have no info..
Without information, you cannot get control of any Bitcoin your brother possessed.
You need some details of his wallet or of his account with a Bitcoin exchange.
How do I retreive
If he looked after his own money in a Bitcoin wallet on a computer or phone, you need to be able to log in to that device and run the wallet program and enter any password he set on the wallet. He may have kept a note of his wallet’s “private key” or its 12, 18 or 24-word “recovery phrase” written down somewhere safe. E.g. on paper or stamped metal in a safe. If so, you can use this information on a different computer to create a new wallet that controls the same money.
If he had an account with a business that looked after his money for him, you’ll need to find out the name of that business and his login details. It is possible you would find some details in his old email messages.
I have death certificate.
That might be of use if his money was in an exchange and you know his account name but not his account password. You or the executor of his estate would need to contact the exchange directly about this.
You will be contacted by people offering to help you. 99% of these will be scammers intending to trick you into trusting them with any details you find, or who will trick you into paying invented recovery fees but who will never give you access to your brother’s money. Be very very careful.