they can get bitcoin in paper form like what you get when using Bitcoin ATM.
pieces of paper with public and private address after that they can import the private key to any wallet "just show the private key to any scanner" and get the money.
Important point
you must have some knowledge and internet access to use bitcoin.
Considering they will have enough knowledge and resources to use Bitcoin, they can but lets be honest here, we know that it would be hard for them to use it becuase they lack the essentials to fully use cryptocurrencies.
Another thing is that, if they will exchange their fiat money for bitcoin, it would be possible that they can much less that the actual amount of their money.
Lets make this thread more conversational. What if these beggars gets a considerable amount of BTC or Crypto's, would they exchange it for Fiat or just hold and let it grow for a while. Assuming they have a knowledge of how crypto's work. LOL