thank you for sharing your question with the Wefugees community.
Most lawyers accept instalment payments, e.g 50,- € monthly until the procedure is finished, so your friend could ask his lawyer for an instalment contract. But it is important that he pays at least a small advance, otherwise his lawyer might refuse to do anything.
He could also seek free consultation in North Rhine-Westphalia. A list of organisations who offer help can be found here: https://www.frnrw.de/fileadmin/frnrw/media/downloads/netzheft/Netzheft_2020.pdf.
I hope my answers were helpful and I’ll be very pleased if you contact me again with further questions. I'm a consultant with mbeon and I‘ll be glad to guide you over a longer period of time. mbeon is an online advisory service for migrants via app, which you can download on your smartphone for free. You'll find me in the mbeon-app under my name „München, Frau Müller“ and get confidential one-to-one advice in a safe virtual room where nobody can read messages. For further information please visit www.mbeon.de.