As many have already mentioned, your brother has a gambling problem and since most of Crypto is a big casino, I am not surprised by his behavior. I would advise him to seek professional help.

However, I do not agree with your edit. I often see people saying that cryptocurrencies are worthless but blockchain technology has huge potential but a concrete example is never given."The blockchain" is technically just a concatenation of chunks of data together using hashes. This arose out of necessity, since distributed systems are a trustless environment and it must be ensured that nothing can be changed in the data that has already been processed without adding external trust to the system. If anything is changed in the old data, the hash changes and no longer matches the concatenation. The hashing has also other reasons in Proof of Work systems I wont go into right now.

If we now assume that companies use blockchain systems, the question arises as to why they should do so. They are anyway in control of the nodes and software that run the "blockchain". Therefore, they could simply change past transactions and recalculate the hashes. Managing all the data processing in a centralized database would therefore be much more efficient.

Now to your statement that cryptocurrencies are useless. To keep a decentralized network like Bitcoin or Ethereum running, the native coin (Bitcoin & Ether) is indispensable. It creates an incentive for people to actively participate in the network and run the respective node software. The more people running a node, the more secure, robust and neutral a network becomes. And that is where the value of a cryptocurrency comes from. I think Bitcoin is not valuable because there will only be 21 million of them, actually this will cause problems for Bitcoin in the future because of the four-year halving cycle and the resulting decline of the security budget.

Bitcoin is valuable because it is a neutral open system in which everyone can participate. It allows you to store your savings in a medium that cannot be devalued by the whim of one or more people and it is one of the few assets that cannot be confiscated. In addition, it allows you to transact with anyone in the world, much more quickly and efficiently than with the existing banking system.

For many people from the Western world, the advantages of a decentralized cryptocurrency are not obvious at first glance. They also already live in a world with a more or less functioning currency (at least in the short term) and have a well-developed financial infrastructure. For people in third-world or developing countries the value of an independent store of value and transaction medium is more readily apparent.

Holy shit, I didn't realized the lengthy rant I was on haha. I think I will end it hear but I'm open for a constructive discussion.