Retrieving ETH from deceased sibling

Hi all. My younger brother died last week at a very young age and he has invested quite a lot in ETH. I am unsure of whether I have in possession of all of the investments, but I have a nano ledger s and some encrypted information on several USBs (he had always said he sent those to me for backup purposes). I think he used truecrypt to encrypt these USBs. There is also a SSD with what I believe would be information relating to the account. Obviously I don't want to get hacked or lose access to the money he and my family spent on. Any advice? Any way I can decrypt the information on the USBs? I know that nobody on the internet can be trusted and I do have some family/close friends who are knowledgable with computers/coding, but I would like to know more before handing over such precious information and possibly lose access or currency in the process through stupid mistakes.

TL;DR: brother died suddenly, need to ensure safest/best way to retrieve ETH and transfer it to an account of my own or withdraw it somehow.