Since I do not know all of the specifics of your medical treatment or what you believe your surgeon's deviation from the applicable standards of care are, I can only make general comments and provide you an example of what I believed was medical malpractice by the orthopedic surgeon who performed my second right (dominant arm) shoulder/arm surgery in June 2016. Also, I work in the Insurance/Finance industry and as part of my job, I am tasked with determining if a business (including hospitals, nursing homes, physicians, etc...) have been negligent, reviewing medical records, IME reports, depositions, etc... One other person who commented on your question was spot-on when he/she said that pursuing a medical provider for medical malpractice can be extremely difficult and I can tell you it is VERY expensive for you (the patient or Plaintiff if a lawsuit actually ever gets filed).
In general with all negligence cases, the following applies: A person who alleges negligent medical malpractice must prove four elements: (1) a duty of care was owed by the physician; (2) the physician violated the applicable standard of care; (3) the person suffered a compensable injury; and (4) the injury was caused in fact and proximately caused by the substandard conduct. The burden of proving these elements is on the plaintiff in a malpractice lawsuit. To simplify, (1) Duty must be owed to you in the first place, (2) duty breached, (3) compensable injury (many states REQUIRE permanent injury) and (4) Injury is causally related to the breach of the duty owed. With my own belief of medical malpractice in the State of Ohio where I as well as the surgeon resides, I faced a plethora of insurmountable obstacles including but not limited to: (1) the statute of limitations/every state has one for each different tort; in Ohio, medical malpractice has a 1 year statute of limitations with some exceptions such as date of discovery; (2) Tort reform - even if I prevailed in my lawsuit, my damages (the money I would receive for so-called pain & suffering was capped at $250,000 unless it was a catastrophic injury and then it was still only $500,000; (3) Very expensive & risky for me to file a lawsuit, retain expert witnesses to prove the alleged medical malpractice; I was looking at paying up to $100,000 for medical experts just to pursue the med mal case and if I would have filed a lawsuit & probably would have lost - I would be stuck with the cost of medical experts; (4) my medical experts as well as my plaintiff attorney would have to be from out of the State of Ohio because the qualified plaintiff attorneys were "conflicted out" as they had a working relationship with my surgeon since plaintiff attorneys handle med mal cases but they also handle personal injury cases and the attorneys that I consulted with stated that I would NEVER find another physician in the State of Ohio to "stab another doctor in the back" by testifying against my surgeon; (5) comparative negligence - the defense attorney could & would have argued that my surgery was unsuccessful because of my pre-existing condition & prior surgery; any comparative negligence applied to me would reduce any settlement if I did win or possibly even bar me from recovery at all.
I also find it perplexing that a number of physicians have told you to sue this other doctor. I have never heard of that happening except maybe a chiropractor (who treats accident victims) and I don't even consider a chiropractor a "real" doctor because they are not. M.D.s or D.O.s simply do not throw other physicians under the proverbial bus because then that makes them a target and their referrals from other doctors would dramatically dry up to nothing.
You indicate a friend sued a nursing home and settled out of court. I'm only guessing but I suppose your friend may have alleged nursing home neglect or something to that effect. With medical malpractice, settling out of court is a rarity. Medical malpractice insurance gives the insured aka the physician the exclusive decision-making authority to settle or to take the case to trial. This is because it is not a simple auto insurance claim; med mal claims have an long-lasting, negative impact on the physician, his/her reputation, etc...so the physician will fight tooth & nail and their med mal insurer will foot the bill.
I never filed a med mal lawsuit in relation to the orthopedic surgeon who performed my 2nd surgery because even though I had medical reports from the 3rd orthopedic surgeon who had to fix the mistakes "implying" that the 2nd surgeon screwed up. That was all I had was records that "implied" med mal by the prior surgeon. My 3rd surgeon refused to directly state verbally or in writing that my prior surgeon butchered me. In Ohio, you practically have to die (in which case, your Estate sues) or lose a limb or two before you have a med mal case that a reputable attorney will undertake.
You should certainly consult with a reputable, qualified med mal attorney but if he/she promises you the moon and it sounds too good to be true then odds are that it is too good to be true. After Tort Reform, most states make it extremely difficult even for patients with the proverbial "slam dunk" case to get a dime.