My mother recently passed away. My brother has told me she left everything to him because he has something called TOD (Time of Death) papers.

There is such a thing as TOD accounts in Delaware. If the accounts in this case were titled that way, then the accounts indeed passed directly to your brother. You should ask to see proof of that - it is risky just to take someone's word and assume they are correct.   If she had a Will, then the person in possession of that Will is required to file it with the Register of Wills within 10 days of the date of death. If your brother refuses to do that, then you yourself can apply to be representative of the estate and to handle the assets.