In that case, for me I think generating your address transaction via the Blockchair explorer would have been a better idea while using your Bitcoin wallet address, because it is exactly a typical example of a statement which shows an inflow and outflow of steady income, because he could tell those people that he works in an online firm, whereby he is been paid weekly through Bitcoin, as could be shown in this statement below which I was able to generate via using Blockchair explorer.

All they can see is just ones and zeroes on a digital screen. Do they even understand Bitcoin? The visa officials will not accept bitcoin as “real money”. Even if you show them records of your bitcoin transactions as wage information, they cannot accept it as pay stubs. How can they be sure you own the address? How can they know if it’s not a watch-only wallet? There are just too many unknowns and visa officers do not like having to deal with unknowns in their paperwork. What they are looking for is fiat. All this could be been avoided if the OP’s friend had done his homework before making the visa application.