The deal I made with my surgeon was that he would do a partial if possible, but once he got into my knee if he felt a TKR was needed, that's what he'd do. You see, sometimes it is not possible to see everything that is wrong in xrays or MRI's. In my case there was significant arthritis behind the kneecap that didn't show in any imaging in addition to the loss of cartilage on the inside of the joint that did show up.
This is why you need to find a surgeon you trust and go with their recommendation. And unless your brother is an orthopedic surgeon, I'd pretty much discount his recommendation. Sorry to be so blunt, but you need to make the decision based on opinions of medical professionals. Not everyone has the same things going on and what may have worked for him could be the worse thing for you to do.
One other point....don't be afraid of a TKR. In the months leading up to my surgery, I strongly wanted to avoid having the whole joint replaced. But as two doctors pointed out, a partial sometimes has to be replaced in a couple of years, putting you back into a major surgery situation in a relatively short amount of time.
In the end, my doctor was absolutely correct and I couldn't be happier with my new knee. So do your research (as you have), get multiple opinions (as you have), pick one surgeon and go with the recommendations. You won't regret it.