Why not tell your friend to make a Binance account so that you can directly send BTC to him and exchange it into fiat through P2P?
Because the person is not into crypto and its not feasible for them to start learning now just for this. It's not exactly as simple as creating an email account.
Adding another payment method to your Binance account should be the same name as what you use in your Binance account. So you can't able to use other's bank account to exchange crypto to FIAT.
Is it really adding another payment method? I thought it was
me > p2 seller > me. Not
me > p2 seller > Binance > me. Meaning the seller is the one who is sending the money from their account to the account I give them. It's not Binance that's sending me the money from their account.