Do you have some ideas?
Your friend would be better off selling that amount of bitcoin slowly on centralized exchanges. If he really insists on transacting with the Chinese businessmen, then they can use Western Union's money sending service to send money from China to Europe(but I doubt if that amount of money will be questioned or not by regulators so be careful). Another good way for them to settle their transaction is to follow this tip made by a comment above(I edited it a little in the quote):
why not either you go to EU(China in your friends case) or the buyer will goo china(to Europe) to make the transaction smooth
And meetup would be made in a safe place(specifically near a police station for safety).