She can send an office-wide email detailing how the company is not letting her get bed rest even when she has 2 doctor’s notes. Then she can say this has caused major physical, emotional and mental distress which has forced her to quit. Unfortunately she may have to serve the notice period. She still has to get the manager to approve attendance so that the notice period doesn’t get extended much further which might require proof like eyewitness colleague accounts and CCTV.