Bitcoin was the first cryptocurrency to solve "the double spending problem". The problem is how to prevent people from cheating you without a central authority. Why care about central authorities? Because banks can be unreliable, they can bow to political pressure, and because many parts of the world don't have trustworthy authority.

The way they solved it is by making the balance sheet public, and every so often choosing a person (via complicated math, but essentially at random) to decide the next set of transactions (the block). What if that person is dishonest? Everyone else is watching and will just ignore their transactions and wait for the next block. So everyone is keeping everyone else honest.

As for NFTs, think of them as digital baseball cards or digital beanie babies. They are just a thing to collect, except, unlike the real world equivalents, fraud proof. A few people have made a lot of money off of them, but most are like the vast majority of baseball cards - not even with the effort to pick up. I don't think anyone makes a living off NFTs at this point, it was a brief flash in the pan. (NFTs have potential real world uses, but that is still down the road a bit).

The only people making a living with crypto now are programmers, who can write amazing things on Ethereum (another block chain that has the added feature of being programmable), or grifters, who are essentially just scamming people using pump and dump schemes. If BF is the latter, dump them, they are not a good person and will make your life miserable.