Colleague of mine is getting railed by their salary.

The salary is based on 30 hours per week so they have time to focus on their own stuff, but being in the medical field, there's a certain amount of obligation to patients and the company packs the schedule as tightly as possible, so they realistically work around 60h/w while only being paid for 30.

Over the last year the company has profited immensely from this arrangement. When my colleague threatened to leave unless reimbursed, the companys response was to issue a pay raise, which calculates out to about +4$ per hour going forward and does nothing to address all the past and future unpaid labor. Nothing has even actually changed yet either; upper management is constantly dragging their feet and playing dumb to drag this whole thing out for profits.

Because of patient obligations, it's impossibly to just up and leave. Plus, they've almost definitely signed away the right to sue in favor of arbitration. Does anyone have any ideas or advice regarding the possibility of salvaging this situation? The more I write, the more it becomes clear that nothing will actually change.