Do I have legal recourse against a physician who caused my disability case to be closed because he confused me with another patient?

You need to immediately appeal and contact that physician and explain what occurred and tell the physician verbally and in writing to make it right or his actions (negligent actions) will be reported to the medical board and you will seek legal counsel to sue him, his office and the insurance company for violations stemming from malpractice to HIPAA violations.  He has revealed personal and private medical information of your cousin and your cousin may indeed have a HIPAA violation case, If this is her physician too, have her visit the doctor with you and explain what occurred. Be firm and explain what occurred. Document everything and have your cousin get a power of attorney (limited one) from you to discuss your case with your insurance company or have her simply explain what occurred to the insurance company. File a consumer complaint with the Attorney General in Pennsylvania against the doctor and also one against the insurance company. The complaint against the insurance company should be also forwareded to your state's department of insurance.

Prior to filing a lawsuit, contact the doctor's office and inquire if they can correct the problem with the insurance company so that your benefits can be restored. Ask to speak with the doctor and not just someone in the records department.  If that isn't feasible, proceed with a lawsuit.

You could sue the doctor for negligence for confusing your records with those of your relative.  Negligence is based on the failure to exercise due care (that degree of care that in this case a reasonable physician in the same community would have exercised under the same or similar circumstances to prevent foreseeable harm).  In order to prove negligence, you will have to prove duty (failure to exercise due care discussed above), breach of duty (confusion of the medical records), actual cause, proximate cause, damages.  Actual cause means but for the doctor confusing your records with those of your relative, would your  disability benefits have been terminated?  If the answer is no, which appears to be the case, you have established actual cause.  Proximate cause means were there any unforeseeable intervening events which would relieve the doctor of liability?  If the answer is no, which appears to be the case, you have established proximate cause.  Damages refers to the amount of compensation you are seeking in your lawsuit.  Damages would be based on the amount of benefits you have lost and expenses you have incurred as a result of the lost benefits.

You will need to file your lawsuit prior to the expiration of the applicable statute of limitations or you will lose your rights forever in the matter.