Final answer:
The doctor is most likely recommending Keegan try an invasive procedure like electroconvulsive therapy (ECT), deep brain stimulation (DBS), or vagus nerve stimulation (VNS) as a final option to treat his severe depression.
Step-by-step explanation:
If Keegan has been suffering from very severe depression and has not found relief from medications or therapies, the doctor might be suggesting an invasive procedure known as electroconvulsive therapy (ECT). ECT is often considered when other treatments for depression have failed. It involves a brief electrical stimulation of the brain while the patient is under anesthesia. Another less common but invasive option might be deep brain stimulation (DBS), where electrodes are implanted in certain areas of the brain, or vagus nerve stimulation (VNS), which involves implantation of a device that sends electrical signals to the brain via the vagus nerve.
These treatments are typically used as a last resort when other forms of therapy have not been effective. It's also worth noting that ECT has a high success rate in treating severe depression, but it can have side effects, including temporary memory loss. Before proceeding with any invasive treatment, Keegan would have to be comprehensively assessed, and the potential benefits and risks would need to be weighed thoroughly.