B4S, you are not bonded in Ryanair because the company did not pay for your type rating.
Bluebaron, your friend needs to read his contract and see what he signed up to. If he agreed to a bond and wants to leave early then he needs to buy his way out. It is not an unauthorized deduction from his pay if he authorized it by agreeing to it in the contract. As Alexander said, it is probably preferable to buy his way out pre-tax rather than using taxed future income.
I have little sympathy for pilots who jump their bonds - the airlines who invest in a pilot are rightly aggrieved if they don't get a return of service and that is probably partly responsible for airlines requiring pilots to self fund TRs.